Analysis by: jasperm
ALIASES:

Sophos : Mal/TDSSPack-Z

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

It drops and executes a file detected as BKDR_TDSS.JAS.

This Trojan may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

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

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 150,016 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 06 Dec 2010
Payload: Drops files

Arrival Details

This Trojan may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops and executes the following files:

  • %User Temp%\{random}.TMP - malicious .sys file detected as BKDR_TDSS.JAS

(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.)

Autostart Technique

This Trojan registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random}
ImagePath = %User Temp%\{random}.TMP

Dropping Routine

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

Other Details

This Trojan deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.685.80
VSAPI PATTERN Date: 06 Dec 2010
VSAPI PATTERN Date: 12/6/2010 12:00:00 AM

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_AGENT.EYEH

    •  BKDR_TDSS.JAS

Step 3

Delete this registry key

[ 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\SYSTEM\CurrentControlSet\Services
    • {random}

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT.EYEH. 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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