TROJ_VUNDO.SMEO1

June 18, 2013
 ALIASES:

TrojanDropper:Win32/Vundo.J (Microsoft); Vundo.gen.dp (McAfee); Trojan.Gen.2 (Symantec); Trojan-Downloader.Win32.DNSKrab.boa (Kaspersky); Virtumonde (Sunbelt); Gen:Heur.IPZ.6 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • 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.

  TECHNICAL DETAILS

File Size:

131,072 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Sep 2012

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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
fccdabaudio = "rundll32.exe khgday.dll,s"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
efdayaaudio = "rundll32.exe khgday.dll,s"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\de5dcde712570306ac8e312c0d1f0b1f

Dropping Routine

This Trojan drops the following files:

  • %System%\khgday.dll

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

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

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_CURRENT_USER\Software
    • de5dcde712570306ac8e312c0d1f0b1f

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • fccdabaudio = "rundll32.exe khgday.dll,s"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • efdayaaudio = "rundll32.exe khgday.dll,s"

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.
  • %System%\khgday.dll

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VUNDO.SMEO1. 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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