BKDR_SHOTODOR.VF

February 19, 2015
 Analysis by: RonJay Kristoffer Caragay
 ALIASES:

Trojan-Dropper.Win32.SFX.fz (Kaspersky); Troj/Malit-EX (Sophos); W32/SFX.FZ!tr (Fortinet); Trojan.Ciusky.Gen.8 (F-Secure);

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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:

1,160,326 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Feb 2015

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 adds the following folders:

  • %User Profile%\69kf52rh

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

It drops the following files:

  • %User Profile%\69kf52rh\iexplore.exe
  • %User Profile%\69kf52rh\luzitt
  • %User Profile%\69kf52rh\ouwcgtopts.MVM
  • %User Profile%\69kf52rh\run.vbs
  • %User Profile%\69kf52rh\tfqjmfndmfd.WBG
  • %User Profile%\69kf52rh\tjdobzhlvplscj.cmd
  • %User Profile%\69kf52rh\ujcw.vbs

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

Autostart Technique

This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
%User Profile%\69kf52rh = "%User Profile%\69kf52rh\ujcw.vbs"

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.470.02

FIRST VSAPI PATTERN DATE:

10 Feb 2015

VSAPI OPR PATTERN File:

11.471.00

VSAPI OPR PATTERN Date:

11 Feb 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • %User Profile%\69kf52rh = "%User Profile%\69kf52rh\ujcw.vbs"

Step 5

Search and delete this file

[ 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.  
  • %User Profile%\69kf52rh\iexplore.exe
  • %User Profile%\69kf52rh\luzitt
  • %User Profile%\69kf52rh\ouwcgtopts.MVM
  • %User Profile%\69kf52rh\run.vbs
  • %User Profile%\69kf52rh\tfqjmfndmfd.WBG
  • %User Profile%\69kf52rh\tjdobzhlvplscj.cmd
  • %User Profile%\69kf52rh\ujcw.vbs

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\69kf52rh

Step 7

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