Analysis by: Mark Joseph Manahan
ALIASES:

Trojan:Win32/Dynamer!dtc (Microsoft), Trojan-FakeAV.Win32.SmartFortress2012.ajzw (Kaspersky), RDN/TDSS.d!c (McAfee)

 PLATFORM:

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

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 9,728 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 11 Nov 2013

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.

Installation

This Trojan drops the following non-malicious file:

  • %Application Data%\d69f7857s5d86978s5d6.jpg

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Other System Modifications

This Trojan deletes the following files:

  • {Malware Path}\z9g88d86f70g8h9f96d86f9gh
  • {Malware Path}\f7g807968d6f97g8079ff97g

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}.{BLOCKED}.163.177/soft.exe

It saves the files it downloads using the following names:

  • %Temp%\8d69f768d69f786d69f7968d6f79.exe

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.300
VSAPI OPR PATTERN File: 10.405.00
VSAPI OPR PATTERN Date: 12 Nov 2013

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

Search and delete these files

[ Learn More ]
There may be some 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.  
  • %Application Data%\d69f7857s5d86978s5d6.jpg
  • %Temp%\8d69f768d69f786d69f7968d6f79.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_ONKODS.SMA. 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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