WORM_PALEVO.SMQX

 Analysis by: Christopher Daniel So

 ALIASES:

Trojan:Win32/Rimecud.A (Microsoft), Trojan.Win32.Pincav.apnc (Kaspersky), Mal/Palevo-A (Sophos), W32/PalevoPack.A!tr (Fortinet), Trojan.Win32.Rimecud (Ikarus)

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm drops copies of itself in all removable drives. 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:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

17 Dec 2010

Installation

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

  • %User Profile%\{random file name}.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.)

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = "%User Temp%\{random file name}.exe"

Propagation

This worm drops copies of itself in all removable drives.

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]
USEAUTOPLAY=1
shellexecute=mashatasha\\{random file name}.exe
shell\Install\command=mashatasha\\{random file name}.exe
shell\open\command=mashatasha\\{random file name}.exe
shell\explore\command=mashatasha\\{random file name}.exe
Shell\open\command=mashatasha\\{random file name}.exe
open=mashatasha\\{random file name}.exe
Icon=mashatasha\\{random file name}.exe
%%%%%%%
action=Open folder to view files using Windows Explore

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.707.00

VSAPI PATTERN Date:

18 Dec 2010

VSAPI PATTERN Date:

12/18/2010 12:00:00 AM

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as WORM_PALEVO.SMQX

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete the file detected as WORM_PALEVO.SMQX

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 5

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 Temp%\{random file name}.exe

Step 6

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

[ Learn More ]
[autorun]
USEAUTOPLAY=1
shellexecute=mashatasha\\{random file name}.exe
shell\Install\command=mashatasha\\{random file name}.exe
shell\open\command=mashatasha\\{random file name}.exe
shell\explore\command=mashatasha\\{random file name}.exe
Shell\open\command=mashatasha\\{random file name}.exe
open=mashatasha\\{random file name}.exe
Icon=mashatasha\\{random file name}.exe
%%%%%%%
action=Open folder to view files using Windows Explore

Step 7

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