Analysis by: Karl Dominguez
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via instant messaging applications, Propagates via peer-to-peer networks

This worm 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: 221,849 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Aug 2010
Payload: Drops files, Launches DoS/DDoS attacks, Hides files and processes

Installation

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

  • %System Root%\RECYCLER\{SID}\MsMxEng.exe

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

It drops the following file(s)/component(s):

  • %System Root%\RECYCLER\{SID}\Desktop.ini
  • {drive letter}:\bar32\desktop.ini

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

It injects threads into the following normal process(es):

  • Explorer.exe

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
Taskman = "%System Root%\RECYCLER\{SID}\MsMxEng.exe"

Propagation

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

  • {drive letter}:\bar32\bar32.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:

;{garbage}
[autorun
;{garbage}
open=bar/bar32.exe
;{garbage}
icon=SHELL32.dll,4
;{garbage}
acTIon=Open folder to view files using Windows Explorer
;{garbage}
shElL\oPEn\commaNd=bar\\\\\\\\\\\bar32.exe
;{garbage}
SheLl\\\\\\\\exPLore\\\\\\\\\comMand=bar/////////bar32.exe
;{garbage}
useautoplay=1
;{garbage}

It sends copies of itself to target recipients using the following instant-messaging (IM) applications:

  • MSN Messenger

Dropping Routine

This worm sets the attributes of its dropped file(s) to the following:

  • Hidden
  • Read Only
  • System

Other Details

Based on analysis of the codes, it has the following capabilities:

  • Propagates through the following P2P applications:
    • Kazaa
    • BearShare
    • iMesh
    • Shareaza
    • DC++
    • Emule
    • LimeWire
    • Ares
  • Performs denial of service (DoS) attacks on affected systems using SYN flooding
  • Drops an AUTORUN.INF file detected as TROJ_OTORUN.RL

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 7.364.13
VSAPI OPR PATTERN Date: 06 Aug 2010

Step 1

Remove malware files dropped/downloaded by WORM_KOLAB.RL

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\
    • Taskman=%System Root%\RECYCLER\{SID}\MsMxEng.exe

Step 3

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\RECYCLER\{SID}\
  • {drive letter}:\bar32

Step 4

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


Did this description help? Tell us how we did.