Analysis by: Anthony Joe Melgarejo
ALIASES:

Trojan:Win32/Alureon.gen!J (Microsoft), Packed:W32/TDSS.gen!A (F-Secure), Trojan.Win32.Alureon.jaa (v) (VIPRE), W32/Alureon.B!Generic (F-Prot), W32/PackTDssfilter.I!tr (Fortinet), Packed.Win32.Tdss (Ikarus), Trj/TDSS.gen (Panda), Trojan.TDSS.01414 (VBA32)

 PLATFORM:

Windows 2000, Windows XP (32-bit and 64-bit), Windows Server 2003, Windows Vista (32-bit and 64-bit), Windows 7 (32-bit and 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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 may be downloaded by other malware/grayware/spyware from remote sites.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 98,304 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 06 Nov 2009
Payload: Drops files

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.

It may be downloaded by other malware/grayware/spyware from remote sites.

Installation

This Trojan drops the following files:

  • %User Temp%\UAC{random characters 2}.tmp - WORM_TDSS.SMY
  • %User Temp%\UAC{random characters 3}.tmp - PTCH_TDSS.XY

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following copies of itself into the affected system:

  • %User Temp%\UAC{random characters 1}.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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other Details

This Trojan deletes the initially executed copy of itself

NOTES:
The Trojan exploits the following vulnerability to execute the dropped WORM_TDSS.SMB malware:

It patches the legitimate file %System%\msvcrt.DLL then starts the normal service msiserver to load the WORM_TDSS.SMB malware.

The patched %System%\msvcrt.DLL is detected as PTCH_TDSS.XY.

This malware does not continue with its routines and will terminate if the affected system's locale is any of the following:

  • Azerbaijan
  • Belarus
  • Kazakhstan
  • Kyrgyzstan
  • Russia
  • Uzbekistan
  • Ukraine

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 6.608.04
FIRST VSAPI PATTERN DATE: 06 Nov 2009
VSAPI OPR PATTERN File: 6.609.00
VSAPI OPR PATTERN Date: 06 Nov 2009

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product and note files detected as TROJ_ALUREON.AWL

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Remove the malware/grayware file dropped/downloaded by TROJ_ALUREON.AWL

    • WORM_TDSS.SMY
    • PTCH_TDSS.XY

Step 5

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

Step 6

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors. Microsoft Security Bulletin MS99-006


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