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BKDR_POISON.BRJ

May 10, 2013
 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:

  • 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:

86,016 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 May 2013

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 copies of itself into the affected system:

  • %Windows%\woekfk.exe

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

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CLASSES_ROOT\My20130401.Document

HKEY_CLASSES_ROOT\My20130401.Document\DefaultIcon

HKEY_CLASSES_ROOT\My20130401.Document\shell

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open\command

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open\ddeexec

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print\command

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print\ddeexec

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto\command

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto\ddeexec

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto\ddeexec

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
20130401

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
20130401\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
20130401\Settings

It adds the following registry entries:

HKEY_CLASSES_ROOT\My20130401.Document
(Default) = "My2013 Document"

HKEY_CLASSES_ROOT\My20130401.Document\DefaultIcon
(Default) = "{malware path}\{malware file name}.exe,1"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open\command
(Default) = "{malware path}\{malware file name}.exe /dde"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open\ddeexec
(Default) = "[open("%1")]"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print\command
(Default) = "{malware path}\{malware file name}.exe /dde"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print\ddeexec
(Default) = "[print("%1")]"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto\command
(Default) = "{malware path}\{malware file name}.exe /dde"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
printto\ddeexec
(Default) = "[printto("%1", "%2", "%3", "%4")]"

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://baby.{BLOCKED}linux.net

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.906.04

FIRST VSAPI PATTERN DATE:

09 May 2013

VSAPI OPR PATTERN File:

9.907.00

VSAPI OPR PATTERN Date:

10 May 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

Scan your computer with your Trend Micro product and note files detected as BKDR_POISON.BRJ

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete the files detected as BKDR_POISON.BRJ

*Note: Some component files may be 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.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 5

Delete this registry key

[ 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_CLASSES_ROOT
    • My20130401.Document
  • In HKEY_CURRENT_USER\Software
    • Local AppWizard-Generated Applications

Step 6

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