ALIASES:

Backdoor:Win32/Farfli.O (Microsoft); [000016b0.EXE]:BackDoor-CKB.gen.q (McAfee); Trojan.Farfli (Symantec); Backdoor.Win32.Agent.bhin (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); MemScan:Backdoor.Generic.613493 (FSecure)

 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

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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 148,376 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 07 Nov 2011

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 creates the following folders:

  • %Program Files%\Vqal

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This backdoor deletes the following files:

  • %System%\syslog.dat
  • %Program Files%\Vqal\Ammijgfjv.bmp
  • %System Root%\Net-Temp.ini

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\326607845

HKEY_LOCAL_MACHINE\SOFTWARE\326607845\
Parameters

HKEY_LOCAL_MACHINE\SOFTWARE\123398766

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\326607845\
Parameters
ServiceDll = "%Program Files%\Vqal\Ammijgfjv.bmp"

HKEY_LOCAL_MACHINE\SOFTWARE\123398766
imgsvc = ""StiSvc,Eqpjuj Ejkmkedf Gqg""

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\RemoteAccess\RouterManagers\
Ip
DLLPath = "%System Root%\2056900.dll"

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

Dropping Routine

This backdoor drops the following files:

  • %System Root%\2056900.dll
  • %System Root%\NT_Path.jpg
  • %Program Files%\Vqal\Ammijgfjv.bmp

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other Details

This backdoor deletes the initially executed copy of itself

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

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\SOFTWARE
    • 326607845
  • In HKEY_LOCAL_MACHINE\SOFTWARE\326607845
    • Parameters
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • 123398766

Step 3

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_LOCAL_MACHINE\SOFTWARE\326607845\Parameters
    • ServiceDll="%Program Files%\Vqal\Ammijgfjv.bmp"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\123398766
    • imgsvc=""StiSvc,Eqpjuj Ejkmkedf Gqg""

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\RemoteAccess\RouterManagers\Ip
    • From: DLLPath="%System Root%\2056900.dll"
      To: DLLPath=%SystemRoot%\System32\iprtrmgr.dll

Step 5

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. %Program Files%\Vqal

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System Root%\2056900.dll
  • %System Root%\NT_Path.jpg
  • %Program Files%\Vqal\Ammijgfjv.bmp

Step 7

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

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System%\syslog.dat
  • %Program Files%\Vqal\Ammijgfjv.bmp
  • %System Root%\Net-Temp.ini


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