Analysis by: kathleenno
 PLATFORM:

Windows 2000, Windows 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

When executed, it connects to servers to receive commands from the remote user. It also attempts to hide its component files by writing specific files at the end of the infected system's hard disk. Trend Micro detects some of these files as BKDR_TDSS.WIM and TROJ_TDSS.WIM. As a result, routines of this backdoor and Trojan are also exhibited on the infected system.

  TECHNICAL DETAILS

File Size: 127,488 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 11 Mar 2011
Payload: Drops files, Hides files and/or processes, Connects to URLs/IP addresses

Installation

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

  • %User Temp%\{random}.tmp

(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 drops the following files:

  • %User Temp%\{temporary file name}.tmp - detected as BKDR_TDSS.WIM

(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 injects codes into the following process(es):

  • SPOOLSV.EXE

NOTES:

Payloads

This Trojan may connect to the following servers where it receives task from a remote malicious user:

  • http://{BLOCKED}1kf-a.com/
  • http://{BLOCKED}-acom.com/
  • http://{BLOCKED}apcell.com/
  • http://{BLOCKED}1come.com/
  • http://{BLOCKED}otcom.com/
  • https://{BLOCKED}agcla.com/
  • https://{BLOCKED}mak01.com/
  • https://{BLOCKED}akq8x.com/

To hide its component files, it writes the following files at the end of the hard disk:

  • \\?\globalroot\{random}\bckfg.tmp
  • \\?\globalroot\{random}\cfg.ini
  • \\?\globalroot\{random}\cmd.dll - detected as TROJ_TDSS.WIM
  • \\?\globalroot\{random}\drv32 - detected as BKDR_TDSS.WIM
  • \\?\globalroot\{random}\drv64 - detected as BKDR_TDSS.WIM
  • \\?\globalroot\{random}\ldr16M
  • \\?\globalroot\{random}\ldr32
  • \\?\globalroot\{random}\ldr64
  • \\?\globalroot\{random}\mbr

  SOLUTION

Minimum Scan Engine: 8.900

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_TDSS.WIN

    • BKDR_TDSS.WIM
    • TROJ_TDSS.WIM

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_TDSS.WIN. 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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