Analysis by: Abraham Latimer Camba
 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

Infection Channel: Dropped by other malware

This backdoor may be dropped by other malware.

It is injected into all running processes to remain memory resident.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

Ports: Port 80
File Size: 300,264 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 07 Sep 2012
Payload: Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_MAXIMUS.HU

Installation

This backdoor creates the following folders:

  • %Temp%\TEMP

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)

It is injected into all running processes to remain memory resident.

Backdoor Routine

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

  • Create/delete/modify registry entries
  • Create/terminate/enumerate processes
  • Get system information
  • Log keystrokes
  • Manage application windows
  • Open/create/delete/modify files and folders
  • Open/create/delete/modify services
  • Perform remote shell
  • Restart/shutdown system
  • Take screenshots of the system

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

  • {BLOCKED}.{BLOCKED}.172.177:80

It posts the following information to its command and control (C&C) server:

  • Computer name
  • Drive information
  • Operating system information
  • Processor speed
  • RAM Information
  • Save email password
  • Saved email address
  • Service pack information
  • System settings
  • User name and cached password

NOTES:

This backdoor checks if it is running under the following processes:

  • 360rp.exe
  • 360safe.exe
  • 360sd.exe
  • 360tray.exe
  • avp.exe
  • dsmain.exe
  • dumprep.exe
  • iexplore.exe
  • lsass.exe
  • svchost.exe

It is registered as a Layered Service Provider (LSP) in order to gain ability to manage inbound and outbound network traffic on the computer.

  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

Remove the malware/grayware file that dropped/downloaded BKDR_WOLYX.AA

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_WOLYX.AA

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the file detected as BKDR_WOLYX.AA

*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

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Temp%\TEMP

Step 7

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