Analysis by: JasperM

 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm drops copies of itself into all the removable drives connected to an affected system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 140800 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 13 May 2010

Installation

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

  • %System Root%\RECYCLER\S-1-5-21-2039539078-8507012708-643120080-8363\mwau.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It injects itself into the following processes running in the affected system's memory:

  • EXPLORER.EXE

It creates the following folders:

  • %System Root%\RECYCLER\S-1-5-21-2039539078-8507012708-643120080-8363
  • %System Root%\RECYCLER

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %System Root%\RECYCLER\S-1-5-21-2039539078-8507012708-643120080-8363\mwau.exe

Propagation

This worm creates the following folders in all removable drives:

  • winamp_cache_0001

It drops copies of itself into all the removable drives connected to an affected system.

It drops the following copy(ies) of itself in all removable drives:

  • winamp_cache_0001\ehthumbs.exe

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
:jmp0
open=winamp_cache_0001\ehthumbs.exe
:nop
icon=%System%\SHELL32.dll,4
;{garbage characters}
action=Open folder to view files using Windows Explorer
;{garbage characters}
shell\\\\\open\\\\\command=winamp_cache_0001/ehthumbs.exe
shell\\\\explore\\\\\command=winamp_cache_0001/ehthumbs.exe
useautoplay=1
[AutoRun]
;{garbage characters}
:GOTO NUL


(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.)

  SOLUTION

Minimum Scan Engine: 8.900

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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Taskman=%System Root%\RECYCLER\S-1-5-21-2039539078-8507012708-643120080-8363\mwau.exe

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_KOLAB.CQ. 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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