Analysis by: Jimelle Monteser
ALIASES:

Backdoor.Win32.Kelihos (Ikarus), Trojan-PSW.Win32Tepfer.lruv (Kaspersky), Backdoor:Win32/Kelihos.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:
 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.

  TECHNICAL DETAILS

File Size: 825,344 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Jun 2013

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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
SonyAgent = "{malware path}\{malware file name}.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Control\Class\{BEEF1337-DEAD-CACA-6011-553344556666}

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}.123.52/install.htm
  • http://{BLOCKED}.72.102/online.htm
  • http://{BLOCKED}.200.110/start.htm

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.976.01
FIRST VSAPI PATTERN DATE: 12 Jun 2013
VSAPI OPR PATTERN File: 9.977.00
VSAPI OPR PATTERN Date: 13 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

Scan your computer with your Trend Micro product and note files detected as BKDR_KELIHOS.ADE

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\CurrentControlSet\Control\Class
    • {BEEF1337-DEAD-CACA-6011-553344556666}

Step 5

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
    • SonyAgent = "{malware path}\{malware file name}.exe"

Step 6

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