Analysis by: jasperm
ALIASES:

Microsoft: Backdoor:Win32/Farfli.K ; Kaspersky: Trojan-GameThief.Win32.Magania.edjk ; Sophos: Mal/Behav-170

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Backdoor may be dropped by TROJ_DLLSERV.AE.

Its main component registers this malicious .DLL file as a service by creating registry entries.

It opens Port 8883, where it listens for remote commands. It connects to a URL to send and receive commands from a remote malicious user.

Based on its code, it is capable of opening a remote shell, logging keystrokes, creating screen captures, browsing and managing files, checking running services and changing system information.

This backdoor may be dropped by other malware.

  TECHNICAL DETAILS

File Size: 231,971 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 01 Dec 2010
Payload: Connects to URLs/Ips, Steals information

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_DLLSERV.AE

Installation

This backdoor is injected into the following processes running in memory:

  • SVCHOST.EXE

Backdoor Routine

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

  • TCP 8883

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

  • {BLOCKED}.{BLOCKED}.183.34

Other Details

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

  • Opens a remote shell
  • Logs keystrokes
  • Creates screen captures
  • Browses and manages files
  • Checks running services
  • Changes system information

It does the following:

  • Its main component registers this malicious .DLL file as a service by creating the following registry entries:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Irmon\Parameters
    ServiceDll = "%System%\Irmontype.dll"
    ServiceMain = "MainService"

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.667.00
VSAPI PATTERN Date: 01 Dec 2010
VSAPI PATTERN Date: 12/1/2010 12:00:00 AM

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_FARFLI.XU

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • Irmon

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_FARFLI.XU. 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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