Analysis by: Sabrina Lei Sioting
 Modified by: Karl Dominguez

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via removable drives, Propagates via instant messaging applications

This worm arrives by connecting affected removable drives to a system. It arrives via peer-to-peer (P2P) shares.

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: 103,936 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 02 Mar 2011
Payload: Downloads files

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It arrives via peer-to-peer (P2P) shares.

Installation

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

  • %System Root%\RECYCLER\{SID}\wingn.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 files:

  • %System Root%\RECYCLER\{SID}\Desktop.ini

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

It creates the following folders:

  • %System Root%\RECYCLER\{SID}

(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 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 = "%System Root%\RECYCLER\{SID}\wingn.exe"

Propagation

This worm creates the following folders in all removable drives:

  • {drive letter}:\NADFOLDER

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

  • {drive letter}:\NADFOLDER\autorun.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]
open=NADFOLDER\autorun.exe
icon=%System Root%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=NADFOLDER\autorun.exe
shell\open\default=1

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

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

  • MSN Messenger

Other Details

This worm attempts to access the following websites to download files, which are possibly malicious:

  • http://{BLOCKED}.{BLOCKED}.112.145/dq.exe
  • http://{BLOCKED}.{BLOCKED}.112.145/new2.exe
  • http://two.{BLOCKED}raoi.com/lmq.exe
  • http://two.{BLOCKED}raoi.com/m.exe
  • http://two.{BLOCKED}raoi.com/mix.exe
  • http://two.{BLOCKED}raoi.com/serv8.exe
  • http://two.{BLOCKED}raoi.com/sword.exe
  • http://two.{BLOCKED}raoi.com/t122.exe
  • http://two.{BLOCKED}raoi.com/t130.exe
  • http://two.{BLOCKED}raoi.com/t173.exe
  • http://two.{BLOCKED}raoi.com/t18.exe
  • http://two.{BLOCKED}raoi.com/t209.exe
  • http://two.{BLOCKED}raoi.com/t50.exe
  • http://two.{BLOCKED}raoi.com/t98.exe
  • http://two.{BLOCKED}raoi.com/lmq.exe
  • http://two.{BLOCKED}raoi.com/lmq.exe

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.868.07
FIRST VSAPI PATTERN DATE: 02 Mar 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

Identify and delete files detected as WORM_PALEVO.SMU 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 = {malware path and file name}

Step 4

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

[ Learn More ]
[AutoRun]
open=NADFOLDER\autorun.exe
icon=%System Root%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=NADFOLDER\autorun.exe
shell\open\default=1

Step 5

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}:\NADFOLDER

Step 6

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