Analysis by: Michael Cabel

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 55,808 bytes
File Type: PE
Memory Resident: No
Initial Samples Received Date: 17 Jan 2011

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following component file(s):

  • %System%\dll - detected as BKDR_SHIZ.AB
  • %System%\nt.dll - detected as BKDR_SHIZ.AB

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Exists555

Other System Modifications

This Trojan modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\sr\Parameters
FirstRun = 1

(Note: The default value data of the said registry entry is 0.)

Other Details

This Trojan does the following:

  • It patches the following system files:
    • Windows%\explorer.exe - detected as PTCH_BAMITAL.SMX
    • %System%\winlogon.exe - detected as PTCH_BAMITAL.SMX
  • It saves the original files as follows:
    • %Temp%\explorer.dat
    • %Temp%\winlogon.dat

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.772.04
VSAPI PATTERN Date: 17 Jan 2011
VSAPI PATTERN Date: 1/17/2011 12:00:00 AM

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by TROJ_BAMITAL.AJ

    BKDR_SHIZ.AB
    PTCH_BAMITAL.SMX

Step 3

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\sr\Parameters
    • From: FirstRun = 1
      To: 0

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_BAMITAL.AJ. 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.


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