Analysis by: Rhena Inocencio


Backdoor:Win32/Farfli.BD (Microsoft)




  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes


Infection Channel: 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 executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.


File Size: 287,744 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 28 Aug 2014
Payload: 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.


This backdoor drops the following component file(s):

  • {malware path}\fake.cfg - configuration file which can be updated via C&C server
  • %Program Files%\DbProtectSupport\fake.cfg - configuration file which can be updated via C&C server
  • %Program Files%\DbProtectSupport\svchost.exe - detected as BKDR_GATES.XUZL

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

ImagePath = "%Program Files%\DbProtectSupport\svchost.exe"

Start = "2"

It starts the following services:

  • DbProtectSupport

Backdoor Routine

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

  • Perfrom DDOS attack:
    • TCP flooding
    • UDP flooding
    • ICMP flooding
  • Inform status to malicious remote user
  • Terminate attack
  • Update configuration file

It connects to the following websites to send and receive information:


Information Theft

This backdoor s configuration file contains the following information:

  • first line - command (start, stop, type of DDoS attack)
  • second line - range of IP addresses
  • third line - range of ports to be used

It gathers the following data:

  • OS Version
  • Country
  • Network Interface performance (Network Interface({name})\Bytes Total/sec)
  • Processor performance


Minimum Scan Engine: 9.300

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_GATES.XUZL

Step 4

Disable this malware service

[ Learn More ]
    • DbProtectSupport

Step 5

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
    • DbProtectSupport

Step 6

Search and delete these files

[ Learn More ]
There may be some files that are 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.
  • {malware path}\fake.cfg
  • %Program Files%\DbProtectSupport\fake.cfg
  • %Program Files%\DbProtectSupport\svchost.exe

Step 7

Scan your computer with your Trend Micro product to delete files detected as BKDR_GATES.XUZL. 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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