BKDR_AGENT.JVRA

October 09, 2012
 Analysis by: Cris Nowell Pantanilla
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 injects its dropped file/component to specific processes.

  TECHNICAL DETAILS

File Size:

130,048 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Aug 2012

Payload:

Connects to URLs/IPs, Drops files

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 injects its dropped file/component to the following processes:

  • IEXPLORE.EXE

Autostart Technique

This backdoor modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Netman\Parameters
ServiceDll = "{malware path}\tabcteng.dll"

(Note: The default value data of the said registry entry is "%SystemRoot%\System32\netman.dll".)

Other System Modifications

This backdoor modifies the following registry entries:

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

(Note: The default value data of the said registry entry is "3".)

Backdoor Routine

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

  • www.{BLOCKED}or.{BLOCKED}ns.com
  • {BLOCKED}n.{BLOCKED}user.com

Dropping Routine

This backdoor drops the following files:

  • {malware path}\tabcteng.dll - BKDR_AGENT.JVRA

NOTES:

This backdoor is capable of perfoming the following commands:

  • Download/upload File
  • Create/read/delete File
  • List running process
  • List service registry
  • Create/modify/terminate Service
  • Get system information
  • Take screenshot
  • Keylogging
  • Receive shell command
  • Terminate self

  SOLUTION

Minimum Scan Engine:

9.200

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

Scan your computer with your Trend Micro product and note files detected as BKDR_AGENT.JVRA

Step 3

Restart in Safe Mode

[ Learn More ]

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\SYSTEM\CurrentControlSet\Services\Netman
    • From: Start = "2"
      To: Start = "3"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netman\Parameters
    • From: ServiceDll = "{malware path}\tabcteng.dll"
      To: ServiceDll = "%SystemRoot%\System32\netman.dll"

Step 5

Search and delete the file detected as BKDR_AGENT.JVRA

*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 manually delete a malware/grayware file from the affected system:

  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.

Step 6

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


Did this description help? Tell us how we did.