Modified by: Jimelle Monteser
ALIASES:

Packed.Win32.Klone.bq (Kaspersky), PWS:Win32/Frethog.F (Microsoft)

 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:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This spyware 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: 168,960 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Jun 2013

Arrival Details

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

  • {Drive Letter}:\gr.exe
  • %System%\twking.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following component file(s):

  • {Drive Letter}:\autorun.inf
  • %System%\twking0.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
king_tw = "%System%\twking.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\MADOWN

HKEY_LOCAL_MACHINE\Software\Classes\
CLSID\MADOWN

Other Details

This spyware connects to the following possibly malicious URL:

  • http://www.{BLOCKED}2e.com/1tw/at.rar

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.972.05
FIRST VSAPI PATTERN DATE: 10 Jun 2013
VSAPI OPR PATTERN File: 9.973.00
VSAPI OPR PATTERN Date: 11 Jun 2013

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_CLASSES_ROOT\CLSID
    • MADOWN
  • In HKEY_LOCAL_MACHINE\Software\Classes\CLSID
    • MADOWN

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • king_tw = "%System%\twking.exe"

Step 5

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.
  • {Drive Letter}:\gr.exe
  • {Drive Letter}:\autorun.inf
  • %System%\twking0.dll

Step 6

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