HTML_BADEY.A

 Analysis by: Christopher Daniel So

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Trend Micro has flagged this HTML script as noteworthy due to the increased potential for damage, propagation, or both, that it possesses. Specifically, exploits a zero-day vulnerability in IE that could allow remote code execution. This vulnerability exists in an invalid flag reference in several versions of Internet Explorer. Under certain conditions, it is possible to access the invalid flag reference even after an object is deleted. Certain attacks may do this to allow remote code execution.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

It takes advantage of a software vulnerability to download possibly malicious files. After succesfully exploiting the vulnerability, this malware connects to URLs to possibly download other malicious files. It saves the files it downloads using file name %User Temp%\log.gif, detected as BKDR_BADEY.A.

It decrypts the downloaded file to %User Profile%\Application Data\alg.exe. It then executes this executable file. As a result, malicious routines of the downloaded file is exhibited on the affected system. The downloaded file is then deleted by the malware after execution.

This Trojan may be hosted on a website and run when a user accesses the said website.

  TECHNICAL DETAILS

File Size:

20,937 bytes

File Type:

Script

Memory Resident:

No

Initial Samples Received Date:

03 Nov 2010

Payload:

Downloads files

Arrival Details

This Trojan may be hosted on a website and run when a user accesses the said website.

Download Routine

This Trojan takes advantage of the following software vulnerabilities to download possibly malicious files:

After successfully exploiting the said vulnerability, this malware connects to the following URLs to possibly download other malicious files:

  • http://www.{BLOCKED}lub.com/reg/linkbl.gif

It saves the files it downloads using the following names:

Other Details

This Trojan does the following:

  • Decrypts and executes the downloaded file, %User Profile%\Application Data\alg.exe. Doing so executes this malware. As a result, malicious routines of the downloaded file is exhibited on the affected system. The downloaded file is then deleted by this HTML script after execution.

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.593.00

VSAPI OPR PATTERN Date:

03 Nov 2010

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Close all opened browser windows

Step 3

Remove malware files dropped/downloaded by HTML_BADEY.A

Step 4

Scan your computer with your Trend Micro product to delete files detected as HTML_BADEY.A If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 5

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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