TROJ_DRPR.AS

October 09, 2012
 Analysis by: Kathleen Notario
 Modified by: Christopher Daniel So
 ALIASES:

Backdoor.Trojan (Symantec), BackDoor-AMQ.dr (McAfee), Gen:Variant.Zusy.826 (FSecure), Troj/BackDr-FW (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan drops a file detected by Trend Micro as BKDR_POISON.AE.

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

It does not have any propagation routine.

It does not have any backdoor routine.

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

98,304 bytes

File Type:

DLL

Initial Samples Received Date:

19 Mar 2012

Arrival Details

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

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\~TX{random character}.tmp - detected by Trend Micro as BKDR_POISON.AE

(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 files it drops, prompting the affected system to exhibit the malicious routines they contain.

Download Routine

This Trojan does not have any downloading capability.

Information Theft

This Trojan does not have any information-stealing capability.

NOTES:

For this malware to do its routines, it must run inside WINWORD.EXE and it has to have the file name IMESHARE.DLL.

This backdoor does not have rootkit capabilities.

It does not exploit any vulnerability.

It does not communicate through a proxy server.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.850.04

FIRST VSAPI PATTERN DATE:

19 Mar 2012

VSAPI OPR PATTERN File:

8.851.00

VSAPI OPR PATTERN Date:

20 Mar 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 malware files dropped/downloaded by TROJ_DRPR.AS

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DRPR.AS. 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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