BKDR_POISON.BTA

June 19, 2013
 Analysis by: Adrian Cofreros
 Modified by: Abraham Latimer Camba
 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: No

  • In the wild: Yes

  OVERVIEW

This malware uses DLL preloading, a technique more known to be utilized by PlugX.

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

This backdoor arrives as a file that exports the functions of other malware/grayware.

It opens a hidden Internet Explorer window. It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

61,440 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

06 Jun 2013

Payload:

Connects to URLs/IPs, Steals information, Collects system information, Logs keystrokes

Arrival Details

This backdoor arrives as a file that exports the functions of other malware/grayware.

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
GOOGLEBOX SERVER = "{malware path}\vnetlib.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
GOOGLEBOX SERVER = "{malware path}\vnetlib.exe"

Backdoor Routine

This backdoor opens a hidden Internet Explorer window.

It executes the following commands from a remote malicious user:

  • Send system information (Lan IP, Wan IP, Computer name, Username, Account Type, OS)
  • Send hardware information (CPU speed, Memory)
  • Manage Files (Search, Download, Upload, Execute, Rename, Delete)
  • Manage Registries (Search, Modify, Delete, Rename, Create)
  • Manage Processes (View, Kill, Suspend, Unload Module)
  • Manage Services (View, Start, Stop, Edit, Install, Uninstall)
  • Manage Devices (View, Enable, Disable, Remove)
  • Manage Windows
  • Relay server
  • View,copy and uninstall applications
  • View active ports
  • Perform a shell command
  • Download and inject remote codes to legitimate processes
  • Log keystrokes and active window
  • Capture screenshots
  • View webcam activity
  • Listen to microphone audio
  • Update, Uninstall, Restart the malware
  • Retrieve cached passwords and hashes

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}a.{BLOCKED}v.com

Other Details

This backdoor requires the existence of the following files to properly run:

  • {malware path}\vmnetlib.exe

NOTES:

After launching a hidden Internet Explorer window, the malware injects its code to the said process. The said code contains its backdoor routines.

This backdoor is loaded each time the legitimate file VMNETLIB.EXE, located in the same directory, is executed.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.972.09

FIRST VSAPI PATTERN DATE:

10 Jun 2013

VSAPI OPR PATTERN File:

9.973.00

VSAPI OPR PATTERN Date:

11 Jun 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.BTA

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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
    • GOOGLEBOX SERVER = "{malware path}\vnetlib.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • GOOGLEBOX SERVER = "{malware path}\vnetlib.exe"

Step 5

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