Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Copies itself in all available physical drives, Propagates via removable drives

This worm drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 105,757 bytes
File Type: PE
Memory Resident: No
Initial Samples Received Date: 16 Feb 2009

Installation

This worm drops the following copies of itself into the affected system:

  • %System%\rttrwq.exe

(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.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ertyuop = "%System%\rttrwq.exe"

Other System Modifications

This worm modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"

(Note: The default value data of the said registry entry is 1.)

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • s39tg.cmd

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[AutoRun]
;Diw0r049Z8rA4k4w9F74qkw01oKrsSdafwDOal1SsLeisCe5523fai
open=s39tg.cmd
;kSa13Jpasik3wKcsfl2a9laALkj41o283dJowwD4Ldkreo362qmAJZ3AkiddFqrwfjj3sw
shell\open\Command=s39tg.cmd

Other Details

This worm drops the following file(s)/component(s):

  • %System%\mkfght0.dll - detected by Trend Micro as TSPY_ONLINEG.MCL

(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 deletes itself after execution.

NOTES:
The dropped AUTORUN.INF is detected by Trend Micro as Mal_Otorun2.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 5.855.00
FIRST VSAPI PATTERN DATE: 19 Feb 2009

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 WORM_ONLINEG.LAQ

    Mal_Otorun2
    TSPY_ONLINEG.MCL

Step 3

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • ertyuop = "%system%\rttrwq.exe"

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "1"

Step 5

Search and delete AUTORUN.INF files created by WORM_ONLINEG.LAQ that contain these strings

[ Learn More ]
[AutoRun]
;Diw0r049Z8rA4k4w9F74qkw01oKrsSdafwDOal1SsLeisCe5523fai
open=s39tg.cmd
;kSa13Jpasik3wKcsfl2a9laALkj41o283dJowwD4Ldkreo362qmAJZ3AkiddFqrwfjj3sw
shell\open\Command=s39tg.cmd

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_ONLINEG.LAQ. 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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