Analysis by: Karl Dominguez
 Modified by: Jaime Benigno Reyes

ALIASES:

Worm:Win32/Rimecud.B (Microsoft), W32/Rimecud.gen.bm (McAfee), W32.Pilleuz (Symantec), P2P-Worm.Win32.Palevo.bpio (Kaspersky)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from P2P shares, Via removable drives, Downloaded from the Internet, Dropped by other malware

This worm arrives via peer-to-peer (P2P) shares. It arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 352,256 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 13 May 2011
Payload: Compromises system security, Connects to URLs/IPs

Arrival Details

This worm arrives via peer-to-peer (P2P) shares.

It arrives via removable drives.

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

Installation

This worm drops the following component file(s):

  • {malware location}\Desktop.ini
  • %System Root%\RECYCLER\{SID}\Desktop.ini
  • {removable drive letter}:\usecure\desktop.ini

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

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = "{malware location}\{malware name}"

Propagation

This worm creates the following folders in all removable drives:

  • {removable drive letter}:\usecure

It drops copies of itself into the following folders used in peer-to-peer (P2P) networks:

  • Kazaa
  • BearShare
  • iMesh
  • Shareaza
  • DC++
  • Emule
  • LimeWire
  • Ares

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

  • {removable drive letter}:\usecure\usecure32.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 codes}
[autorun
{garbage codes}
open=usecure/usecure32.exe
{garbage codes}
icon=%SystemRoot%\system32\SHELL32.dll,4
;{garbage codes}
action=Open folder to view files using Windows Explorer
;{garbage codes}
USEAUToplay=1
;{garbage codes}
shell\open\command=usecure/usecure32.exe
;{garbage codes}
shell\explore\command=usecure/usecure32.exe
{garbage codes}

Backdoor Routine

This worm opens the following port(s) where it listens for remote commands:

  • 44403

It executes the following commands from a remote malicious user:

  • Performs denial of service (DoS) attacks on affected systems using SYN flooding
  • Steal user credentials
  • Infect network computers using VNC
  • Download arbitrary files
  • Execute arbitrary commands

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • www.{BLOCKED}eslounge.com
  • www.{BLOCKED}racypetition.com
  • www.{BLOCKED}lmind.cn

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 8.154.03
FIRST VSAPI PATTERN DATE: 13 May 2011
VSAPI OPR PATTERN File: 8.155.00
VSAPI OPR PATTERN Date: 13 May 2011

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

Scan your computer with your Trend Micro product and note files detected as WORM_KOLAB.CG

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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\{SID}\MsMxEng.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Taskman = "{malware location}\{malware name}"

Step 5

Search and delete these folders

[ 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}
  • {removable drive letter}:\usecure

Step 6

Search and delete this file

[ Learn More ]
There may be some files 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.
  • {malware location}\Desktop.ini

Step 7

Search and delete AUTORUN.INF files created by WORM_KOLAB.CG that contain these strings

[ Learn More ]
{garbage codes}
[autorun
{garbage codes}
open=usecure/usecure32.exe
{garbage codes}
icon=%SystemRoot%\system32\SHELL32.dll,4
;{garbage codes}
action=Open folder to view files using Windows Explorer
;{garbage codes}
USEAUToplay=1
;{garbage codes}
shell\open\\command=usecure/usecure32.exe
;{garbage codes}
shell\\explore\command=usecure/usecure32.exe
{garbage codes}

Step 8

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