Analysis by: Michael Cabel
 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, 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 logs a user's keystrokes to steal information.

It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size: 133,251 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 28 Feb 2012
Payload: Terminates processes, Steals information, Compromises system security

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.

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_USERS\.DEFAULT\Keyboard Layout\
Toggle
Hotkey = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server\Wds\
rdpwd\Tds\tcp
PortNumber = "0xD3D"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server\WinStations\
RDP-Tcp
PortNumber = "0xD3D"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server\RDPTcp
PortNumber = "0xD3D"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Terminal Server
fDenyTSConnections = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TermService
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\TermDD
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
TSEnabled = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
ShutdownWithoutLogon = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\Installer
EnableAdminTSRemote = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\netcache
Enabled = 0

Backdoor Routine

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

  • TCP 8282

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

  • {BLOCKED}e.wjran.com

Process Termination

This backdoor terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • AYAgent
  • skynet
  • Sophos
  • Jinshan Guardian
  • QQ housekeeper
  • Authentium
  • BitDefender
  • ZoneAlarm
  • Simon
  • Panda
  • Spider
  • Trojan killer
  • Norton
  • avast
  • avira
  • pc-cillin
  • Virus to cattle
  • Kingsoft
  • NOD32
  • McAfee
  • Rising
  • virus.autorun.da
  • kaspersky
  • 360safe

Information Theft

This backdoor logs a user's keystrokes to steal information.

Other Details

This backdoor requires its main component to successfully perform its intended routine.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.806.03
FIRST VSAPI PATTERN DATE: 28 Feb 2012

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

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_USERS\.DEFAULT\Keyboard Layout\Toggle
    • Hotkey = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\rdpwd\Tds\tcp
    • PortNumber = "0xD3D"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp
    • PortNumber = "0xD3D"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RDPTcp
    • PortNumber = "0xD3D"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Terminal Server
    • fDenyTSConnections = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService
    • Start = 2
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermDD
    • Start = 2
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • TSEnabled = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • ShutdownWithoutLogon = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer
    • EnableAdminTSRemote = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\netcache
    • Enabled = 0

Step 3

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