TROJ_RUCKGUV.MJ

 Analysis by: RonJay Kristoffer Caragay

 ALIASES:

Trojan:Win32/Kadena.gen!C (Microsoft); Trojan-Spy.Win32.BitWall.hm (Kaspersky); Troj/Kadena-A (Sophos)

 PLATFORM:

Windows

 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 as attachment to mass-mailed email messages.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

131,072 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

05 Jun 2015

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DownloadManager

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
path = {malware file path}\{malware file name}

Download Routine

This Trojan saves the files it downloads using the following names:

  • %Application Data%\csrss_{random number}.exe
  • %Application Data%\Frifox_{random number}.exe
  • %Application Data%\WindowsDriver_{random number}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • https://{BLOCKED}investments.com/css/putty.exe

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.750

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

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
    • path = {malware file path}\{malware file name}

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\SOFTWARE\Microsoft
    • DownloadManager

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.  
  • %Application Data%\csrss_{random number}.exe
  • %Application Data%\Frifox_{random number}.exe
  • %Application Data%\WindowsDriver_{random number}.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_RUCKGUV.MJ. 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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