Analysis by: adel

 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor may be dropped by other malware.

  TECHNICAL DETAILS

File Size: 118,784 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 31 Mar 2010

Arrival Details

This backdoor may be dropped by the following malware:

  • BKDR_VBOT.A

Autostart Technique

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

HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\
Windows\CURRENTVERSION\Run
Windows Update Automatic Updates = {malware path and file name}

HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\
Windows\CURRENTVERSION\Run
Windows Update Automatic Updates = {malware path and file name}

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

  • TCP port 2121

Other Details

Based on analysis of the codes, it has the following capabilities:

  • Exhibits backdoor routines by attempting to connect to the following servers using TCP post 2121 to listen for commands coming from a remote computer: {BLOCKED}s.ath.cx and {BLOCKED}l.ath.cx
  • Downloads other files including its components, ntconf32.dll, msimsg32.vxd and ntsys32.vxd once a connection is successfully established.
  • Performs the following: changes file attributes, checks drives/list files, creates files/directories, downloads/uploads files, and opens/searches/deletes files

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 6.887.00
VSAPI OPR PATTERN Date: 31 Mar 2010

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

Remove malware files dropped/downloaded by BKDR_VBBOT.AM

    BKDR_VBOT.A

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.

  • In HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Run
    • Windows Update Automatic Updates = {malware path and file name}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Run
    • Windows Update Automatic Updates = {malware path and file name}

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_VBBOT.AM. 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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