BKDR_VENIK

 Analysis by: Wilbert Vidal

 ALIASES:

Backdoor:Win32/Venik.B (Microsoft);

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

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 may be downloaded by other malware/grayware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.

It injects its dropped file/component to specific processes.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

It deletes itself after execution.

  TECHNICAL DETAILS

Payload:

Connects to URLs/IPs, Steals information

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.

It may be downloaded by the following malware/grayware from remote sites:

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Backdoor drops the following files:

  • %Windows%\{number}_Ss.dll - also detected as BKDR_VENIK.AE

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following processes:

  • cmd.exe /c del {malware path}\{malware filename}.exe

It injects its dropped file/component to the following processes:

  • svchost.exe

Other System Modifications

This Backdoor modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{default value} netsvcs_0x0"

(Note: The default value data of the said registry entry is {default value}.)

It creates the following service using its DLL component:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent\Parameters
ServiceDll = "%Windows%\{number}_Ss.dll"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent
DisplayName = "netsvcs_0x0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\apagent
Type = "20"

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Create processes
  • Download and execute files
  • Get OS Version
  • Get Host Name
  • Shutdown Computer
  • Delete services
  • execute iexplorer.exe
  • Send stolen information

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

  • yctou.{BLOCKED}u.com:337

However, as of this writing, the said sites are inaccessible.

Information Theft

This Backdoor gathers the following data:

  • OS Version
  • Host Name
  • System Information
  • Drive Information

Other Details

This Backdoor deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.394.15

FIRST VSAPI PATTERN DATE:

02 Sep 2011

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

Remove the malware/grayware file that dropped/downloaded BKDR_VENIK. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 3

Restart in Safe Mode, and then 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.

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
    • apagent

Step 4

Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • From: netsvcs = "{default value} netsvcs_0x0"
      To: netsvcs = "{default value}"

Step 5

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

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_VENIK. 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 the following Trend Micro Support pages for more information:


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