TROJ_OPACHKI.A

January 30, 2014
 Analysis by: Mark Joseph Manahan
 ALIASES:

Troj/Bredo-RF (Webroot) ,Troj/Bredo-RF (Sophos) ,Trojan horse SHeur4.PLN (AVG) ,W32/Yakes.B!tr (Fortinet) ,W32/Fareit.A.gen!Eldorado (generic, not disinfectable) (Fprot) ,Trojan-Downloader.Win32.Dofoil (Ikarus) ,Trojan:Win32/Opachki.H (Microsoft) ,Trojan-FAAP!68920079F12D (McAfee) ,a variant of Win32/Kryptik.ZZQ trojan (Eset) ,Trojan.Gen (Symantec) ,Bck/Qbot.AO (Panda) ,Trojan.Win32.Bredo.rh (v) (Sunbelt)

 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: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

300,815 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Jan 2014

Payload:

Connects to URLs/IPs, Downloads 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.

Installation

This Trojan drops the following files:

  • %User Profile%\uidsave.dat

(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 copies of itself into the affected system:

  • %User Profile%\winlogon.exe
  • %System%\crrss.exe

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
winlogon = "%User Profile%\winlogon.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "explorer.exe "%User Profile%\winlogon.exe""

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
crrss = "%System%\crrss.exe"

Download Routine

This Trojan accesses the following websites to download files:

  • http://masha.{BLOCKED}e.com/2/z.php

It saves the files it downloads using the following names:

  • %User Profile%\pizda_ntload.dll
  • %User Profile%\pizda_dnsh.dat
  • %User Profile%\pizda_bkurl.dat
  • %User Profile%\pizda_ftp.dll
  • %User Profile%\pizda_cz.dat

(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.)

As of this writing, the said sites are inaccessible.

Information Theft

This Trojan gathers the following data:

  • Operation System and Version
  • Language and Version
  • User ID

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.572.05

FIRST VSAPI PATTERN DATE:

29 Jan 2014

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

Identify and terminate files detected as TROJ_OPACHKI.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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.

  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
  • winlogon = "%User Profile%\winlogon.exe"
  • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
  • shell = "explorer.exe "%User Profile%\winlogon.exe""
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  • crrss = "%System%\crrss.exe"
  • HKEY_CURRENT_USER\Software\Microsoft
  • adver_id = "0"

Step 4

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%\uidsave.dat

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_OPACHKI.A. 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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