Analysis by: Roland Marco Dela Paz
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  TECHNICAL DETAILS

File Size: 25,600 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 17 Nov 2010

Installation

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

  • %System%\spool\prtprocs\w32x86\{random}.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Print\Providers\
{random}.dll
Name = %System%\spool\prtprocs\w32x86\{random}.dll

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.631.00
VSAPI PATTERN Date: 17 Nov 2010
VSAPI PATTERN Date: 11/17/2010 12:00:00 AM

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 BKDR_TDSS.SMF

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ 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\Control\Print\Providers\{random}.dll
    • Name = %System%\spool\prtprocs\w32x86\{random}.dll

Step 5

Search and delete the file detected as BKDR_TDSS.SMF

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.


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