Analysis by: Cris Nowell Pantanilla
 Modified by: Christopher Daniel So
ALIASES:

TrojanDownloader:VBS/Wimmie.A (Microsoft), Backdoor.Trojan (Symantec), Trojan-Dropper.Win32.Small.hjh (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

This Trojan may be dropped by other malware.

It does not have any propagation routine.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size: 49,152 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 16 Jan 2012
Payload: Drops files

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_PIDIEF.EIJ

Propagation

This Trojan does not have any propagation routine.

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\~temp.vbs - detected by Trend Micro as VBS_WIMMIE.SMC

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Download Routine

This Trojan does not have any downloading capability.

Information Theft

This Trojan does not have any information-stealing capability.

NOTES:

This malware does not have rootkit capabilities.

This malware does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.712.07
FIRST VSAPI PATTERN DATE: 16 Jan 2012
VSAPI OPR PATTERN File: 8.713.00
VSAPI OPR PATTERN Date: 17 Jan 2012

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

Remove the malware/grayware file that dropped/downloaded TROJ_WIMMIE.C

Step 3

Remove malware files dropped/downloaded by TROJ_WIMMIE.C

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_WIMMIE.C. 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.