Analysis by: JessaD
ALIASES:

Trojan.Win32.Olmarik.agn (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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

It also has rootkit capabilities, which enables it to hide its processes and files from the user.

  TECHNICAL DETAILS

File Size: Varies
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 06 Jan 2011
Payload: Downloads files

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

  • TROJ_OLMARIK.EFF

Installation

This Trojan drops the following component file(s):

  • %WINDOWS%\WinSxS\x86_Microsoft.Windows.Shell.HWEventDetector_6595b64144ccf1df_5.2.2.3_x-ww_5390e909\shsvcs.dll - also detected as RTKt_OLMARIK.EFF

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{malware filename}
ImagePath = {malware path and file name}.sys

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\*PNP0296\
0000
Service = {malware file name}

It modifies the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{4FA18276-912A-11D1-AD9B-00C04FD8FDFF}\
InprocServer32
@ = %WINDOWS%\WinSxS\x86_Microsoft.Windows.Shell.HWEventDetector_6595b64144ccf1df_5.2.2.3_x-ww_5390e909\shsvcs.dll

(Note: The default value data of the said registry entry is %System%\wbem\wbemcore.dll.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{4FA18276-912A-11D1-AD9B-00C04FD8FDFF}\InprocServer32
@ = %WINDOWS%\WinSxS\x86_Microsoft.Windows.Shell.HWEventDetector_6595b64144ccf1df_5.2.2.3_x-ww_5390e909\shsvcs.dll

(Note: The default value data of the said registry entry is %System%\wbem\wbemcore.dll.)

Rootkit Capabilities

This Trojan also has rootkit capabilities, which enables it to hide its processes and files from the user.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}.130.34/update.db

It saves the files it downloads using the following names:

  • %Windows%\Temp\{random}.tmp

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Trend Micro detects the dowloaded file as:

  • TROJ_DROPPR.EFF

  SOLUTION

Minimum Scan Engine: 9.200

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/grayware files that dropped/downloaded RTKT_OLMARIK.EFF

Step 3

Remove malware files dropped/downloaded by RTKT_OLMARIK.EFF

    • TROJ_DROPPR.EFF

Step 4

Identify and delete files detected as RTKT_OLMARIK.EFF using either the Startup Disk or Recovery Console

[ Learn More ]

Step 5

Delete this registry key

[ 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\
    • {malware filename}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\
    • *PNP0296

Step 6

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_CLASSES_ROOT\CLSID\{4FA18276-912A-11D1-AD9B-00C04FD8FDFF}\InprocServer32
    • From: @ = %WINDOWS%\WinSxS\x86_Microsoft.Windows.Shell.HWEventDetector_6595b64144ccf1df_5.2.2.3_x-ww_5390e909\shsvcs.dll
      To: %System%\wbem\wbemcore.dll.)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{4FA18276-912A-11D1-AD9B-00C04FD8FDFF}\InprocServer32
    • From: @ = %WINDOWS%\WinSxS\x86_Microsoft.Windows.Shell.HWEventDetector_6595b64144ccf1df_5.2.2.3_x-ww_5390e909\shsvcs.dll
      To: %System%\wbem\wbemcore.dll.)

Step 7

Scan your computer with your Trend Micro product to delete files detected as RTKT_OLMARIK.EFF. 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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