BKDR_TDSS.SIP

October 08, 2012
 Analysis by: Cris Nowell Pantanilla
 Modified by: Karl Dominguez
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Oct 2010

Payload:

Compromises system security, Connects to URLs/Ips

Arrival Details

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

Installation

This backdoor drops the following component file(s):

  • %WINDOWS%\Temp\{random}.sys

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

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

(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.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It is injected into the following processes running in memory:

  • SVCHOST.EXE
  • SPOOLSV.EXE

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
PendingFileRenameOperations = %System%\spool\PRTPROCS\W32X86\{random}.dll %User Temp%\{random}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters
NameServer = {BLOCKED}.{BLOCKED}.164.129,93.188.160.209

(Note: The default value data of the said registry entry is {blank}.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters
DhcpNameServer = {BLOCKED}.{BLOCKED}.164.129,93.188.160.209

(Note: The default value data of the said registry entry is {User defined}.)

Backdoor Routine

This backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}.{BLOCKED}.51.17/db.php
  • http://{BLOCKED}.{BLOCKED}.51.17/dbcjs.php
  • http://{BLOCKED}mah.com/dx.php - detected as BKDR_ZLOB.SMGS
  • http://{BLOCKED}mah.com/kx.php - also detected as BKDR_TDSS.SIP

HOSTS File Modification

This backdoor modifies the system's HOSTS files to redirect users once the following Web site(s) are accessed:

  • www.google.com
  • us.search.yahoo.com
  • uk.search.yahoo.com
  • search.yahoo.com
  • www.google.com.br
  • www.google.it
  • www.google.es
  • www.google.co.jp
  • www.google.com.mx
  • www.google.ca
  • www.google.com.au
  • www.google.nl
  • www.google.co.za
  • www.google.be
  • www.google.gr
  • www.google at
  • www.google.se
  • www.google.ch
  • www.google.pt
  • www.google.dk
  • www.google.fi
  • www.google.ie
  • www.google.no
  • www.google.de
  • www.google.fr
  • www.google.co.uk
  • www.bing.com

Other Details

This backdoor does the following:

  • Once the user accesses the sites listed in the HOSTS file, they will be redirected to the following IP Addresses:
    • {BLOCKED}.{BLOCKED}.49.48
    • {BLOCKED}.{BLOCKED}.49.47

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.580.02

VSAPI PATTERN Date:

29 Oct 2010

VSAPI PATTERN Date:

10/29/2010 12:00:00 AM

Step 1

Scan your computer with your Trend Micro product and note files detected as BKDR_TDSS.SIP

Step 2

Remove malware files dropped/downloaded by BKDR_TDSS.SIP

     BKDR_ZLOB.SMGS 

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\Session Manager
    • PendingFileRenameOperations=%System%\spool\PRTPROCS\W32X86\{random}.dll %User Temp%\{random}

Step 5

Restore this modified 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\Services\Tcpip\Parameters
    • From: NameServer={BLOCKED}.{BLOCKED}.164.129,93.188.160.209
      To: NameServer=
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    • From: DhcpNameServer={BLOCKED}.{BLOCKED}.164.129,93.188.160.209
      To: DhcpNameServer={User defined}

Step 6

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result. %System%\spool\prtprocs\w32x86\{random}.dll
%Windows%\Temp\{random}.sys

Step 7

Scan your computer with your Trend Micro product to delete files detected as BKDR_TDSS.SIP. 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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