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TROJ_AGENTB.BI

May 29, 2013
 ALIASES:

Flyagent (McAfee); Downloader (Symantec); Trojan.Win32.Agentb.izp (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Downloader.Generic13.ALUK (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

187,392 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

29 May 2013

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other System Modifications

This Trojan modifies the following file(s):

  • %System%\ws2help.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It deletes the following files:

  • %System%\Drivers\EstRtw.sys
  • %System%\dia3.ini

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\neverdeath
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\neverdeath
ImagePath = "\??\%System%\drivers\xpV3001.sys"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\neverdeath
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\neverdeath
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\neverdeath
ProcessID = "5f"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\420a0a1f
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\420a0a1f
ImagePath = "\??\%System%\drivers\420a0a1f.sys"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\420a0a1f
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\420a0a1f
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\420a0a1f
ProcessID = "5f"

Dropping Routine

This Trojan drops the following files:

  • %Temp%\wr.jpg
  • %Temp%\UnRAR.exe
  • %Temp%\1.vbs
  • %Temp%\1.rar
  • %Temp%\1.exe
  • %System%\drivers\xpV3001.sys
  • %System%\drivers\420a0a1f.sys
  • %System%\ws2helpXP.dll

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://img14.{BLOCKED}o.cn/{random path}

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Delete this 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\ControlSet001\Services\neverdeath
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\neverdeath
    • ImagePath = "\??\%System%\drivers\xpV3001.sys"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\neverdeath
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\neverdeath
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\neverdeath
    • ProcessID = "5f"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\420a0a1f
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\420a0a1f
    • ImagePath = "\??\%System%\drivers\420a0a1f.sys"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\420a0a1f
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\420a0a1f
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\420a0a1f
    • ProcessID = "5f"

Step 3

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Temp%\wr.jpg
  • %Temp%\UnRAR.exe
  • %Temp%\1.vbs
  • %Temp%\1.rar
  • %Temp%\1.exe
  • %System%\drivers\xpV3001.sys
  • %System%\drivers\420a0a1f.sys
  • %System%\ws2helpXP.dll

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENTB.BI. 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

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %System%\ws2help.dll

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System%\Drivers\EstRtw.sys
  • %System%\dia3.ini


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