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BKDR_POISON.BRI

April 26, 2013
 Analysis by: Nikko Tamana
 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:

77,824 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

24 Apr 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.

Other System Modifications

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

HKEY_CLASSES_ROOT\My20130401.Document
Default = "My2013 Document"

HKEY_CLASSES_ROOT\My20130401.Document\shell\
open\command
Default = "{Malware Path and File Name}.exe /dde"

HKEY_CLASSES_ROOT\My20130401.Document\DefaultIcon
Default = "{Malware Path and File Name}.exe,1"

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

HKEY_CLASSES_ROOT\My20130401.Document\shell\
print\command
Default = "{Malware Path and File Name}.exe /dde"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document
Default = "My2013 Document"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\DefaultIcon
Default = "{Malware Path and File Name}.exe,1"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\open\
command
Default = "{Malware Path and File Name}.exe /dde"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\print\
command
Default = "{Malware Path and File Name}.exe /dde"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\printto\
command
Default = "{Malware Path and File Name}.exe /dde"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{GUID}
StubPath = "%Windows%:{random file name}.exe"

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{GUID}

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_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\DefaultIcon

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\open

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\open\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\open\
ddeexec

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\print

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\print\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\print\
ddeexec

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\printto

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\printto\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
My20130401.Document\shell\printto\
ddeexec

Other Details

This backdoor connects to the following possibly malicious URL:

  • https://baby.{BLOCKED}linux.net

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.876.04

FIRST VSAPI PATTERN DATE:

24 Apr 2013

VSAPI OPR PATTERN File:

9.877.00

VSAPI OPR PATTERN Date:

25 Apr 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.BRI

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {GUID}
  • In HKEY_CLASSES_ROOT
    • My20130401.Document
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • My20130401.Document

Step 5

Search and delete the files detected as BKDR_POISON.BRI

*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 6

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