Modified by: Kathleen Notario

ALIASES:

W32.Pilleuz!gen1 (Symantec); Worm:Win32/Rimecud.B (Microsoft); P2P-Worm.Win32.Palevo.avpl (Kaspersky); W32/Palevo.gen.a (Mcafee);

 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: Propagates via removable drives, Propagates via peer-to-peer networks

This worm 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. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 141,312 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 26 Mar 2010
Payload: Compromises system security, Connects to URLs/IPs

Arrival Details

This worm 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 copies of itself into the affected system:

  • %User Profile%\csrss.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It injects itself into the following processes as part of its memory residency routine:

  • 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 = "%User Profile%\csrss.exe"

Propagation

This worm creates the following folders in all removable drives:

  • MUSKO
  • TWINS

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

  • Ares
  • BearShare
  • DC++
  • eMule
  • eMule Plus
  • iMesh
  • Kazaa
  • Limewire
  • Shareaza

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

  • {Removable Drive}:\MUSKO\karikatura.exe
  • {Removable Drive}:\TWINS\jutroivece.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
{garbage characters}
open={folder name}///{malware filename}.exe
{garbage characters}
icon=%SystemRoot%\system32\SHELL32.dll,4
{garbage characters}
action=Open folder to view files using Windows Explorer
{garbage characters}
Shell\open\command={folder name}///{malware filename}.exe
{garbage characters}
shell\open\command={folder name}///{malware filename}.exe
{garbage characters}
USEAUTOPLAY=1
{garbage characters}

It sends messages that contain links to sites hosting remote copies of itself using the following instant-messaging (IM) applications:

  • MSN Messenger

Backdoor Routine

This worm executes the following commands from a remote malicious user:

  • Perform port scans
  • Perform SYN flood
  • Propagate itself via MSN Messenger
  • Propagate itself via P2P networks

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

  • {BLOCKED}t.brand-clothes.net
  • {BLOCKED}a.banjalucke-ljepotice.ru
  • {BLOCKED}a.prichaonica.com

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 6.952.01
FIRST VSAPI PATTERN DATE: 26 Mar 2010
VSAPI OPR PATTERN File: 6.953.00
VSAPI OPR PATTERN Date: 27 Mar 2010

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

Identify and delete files detected as WORM_PALEVO.SMJJ using either the Startup Disk or Recovery Console

[ 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 = "%User Profile%\csrss.exe"

Step 4

Search and delete AUTORUN.INF files created by WORM_PALEVO.SMJJ that contain these strings

[ Learn More ]
[autorun
{garbage characters}
open={folder name}///{malware filename}.exe
{garbage characters}
icon=%SystemRoot%\system32\SHELL32.dll,4
{garbage characters}
action=Open folder to view files using Windows Explorer
{garbage characters}
Shell\open\command={folder name}///{malware filename}.exe
{garbage characters}
shell\open\command={folder name}///{malware filename}.exe
{garbage characters}

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.
  • {Removable Drive}:\MUSKO
  • {Removable Drive}:\TWINS

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_PALEVO.SMJJ. 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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