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TROJ_FARFLI.FPAE

November 04, 2014
 Analysis by: Homer Pacag
 ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft); RDN/Generic BackDoor!b2k (McAfee);

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan 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 itself after execution.

  TECHNICAL DETAILS

File Size:

139,282 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Oct 2014

Arrival Details

This Trojan 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 Trojan drops the following copies of itself into the affected system:

  • %Windows%\{random name}.pif

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Mnopgfhqr Tufgvsdwlxyab Def
DisplayName = Mnopqr Tuvwfgxyfhkab Desdfghijk Mnop

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Mnopgfhqr Tufgvsdwlxyab Def
Description = Mnopqrst Vwxyabscfgde Gdfhijklmjk Opqrstuv Xya

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Mnopgfhqr Tufgvsdwlxyab Def
ImagePath = C:\WINDOWS\{random name}.pif

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Mnopgfhqr Tufgvsdwlxyab Def
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Mnopgfhqr Tufgvsdwlxyab Def
Type = 110

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_MNOPGFHQR_TUFGVSDWLXYAB_DEF\
0000
Class = LegacyDriver

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_MNOPGFHQR_TUFGVSDWLXYAB_DEF\
0000
DeviceDesc = Mnopqr Tuvwfgxyfhkab Desdfghijk Mnop

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_MNOPGFHQR_TUFGVSDWLXYAB_DEF\
0000
Service = Mnopgfhqr Tufgvsdwlxyab Def

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Enum\Root\LEGACY_MNOPGFHQR_TUFGVSDWLXYAB_DEF\
0000\Control
ActiveService = Mnopgfhqr Tufgvsdwlxyab Def

Dropping Routine

This Trojan drops the following files:

  • %System Root%\{random name}.vbs <-deleted afterwards

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}n.{BLOCKED}2.org

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.244.03

FIRST VSAPI PATTERN DATE:

29 Oct 2014

VSAPI OPR PATTERN File:

11.245.00

VSAPI OPR PATTERN Date:

29 Oct 2014

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

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\ControlSet001\Services
    • Mnopgfhqr Tufgvsdwlxyab Def
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root
    • LEGACY_MNOPGFHQR_TUFGVSDWLXYAB_DEF

Step 5

Search and delete this file

[ 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.
  • %Windows%\{random name}.pif
  • %System Root%\{random name}.vbs

Step 6

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