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BKDR_DARKMOON.ZP

October 09, 2012
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This backdoor starts a hidden default browser. It injects codes in the hidden default browser to perform its backdoor routines.

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.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

40,960 bytes

Memory Resident:

Yes

Initial Samples Received Date:

18 Oct 2011

Payload:

Compromises system security

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:

  • %System%\mstanks.exe (if not logged in as an administrator)
  • %System%:mstanks.exe (if logged in as an administrator)

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It injects itself into the following processes running in the affected system's memory:

  • explorer.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • KDJ^&#SF

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{3E01A920-6244-66A3-23E9-6ECFC5C85E01}
StubPath = "%System%:mstanks.exe" or "%System%\mstanks.exe"

Other System Modifications

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

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{3E01A920-6244-66A3-23E9-6ECFC5C85E01}

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

This backdoor starts a hidden default browser. It injects codes in the hidden default browser to perform its backdoor routines.

It connects to email-dns.{BLOCKED}s-mail.com at port 80 to receive binary instructions. It then executes the binary instructions.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.506.02

FIRST VSAPI PATTERN DATE:

18 Oct 2011

VSAPI OPR PATTERN File:

8.507.00

VSAPI OPR PATTERN Date:

19 Oct 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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_CURRENT_USER\Software
    • Local AppWizard-Generated Applications
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {3E01A920-6244-66A3-23E9-6ECFC5C85E01}

Step 4

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