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BKDR_CAPHAW.S

October 23, 2013
 Analysis by: Sabrina Lei Sioting
 ALIASES:

Win32/Caphaw.I (Eset), Trojan.Win32.Bublik.abhh (Kaspersky), VirTool:Win32/CeeInject (Microsoft), Trojan.Ransomlock.G (Symantec),

 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: Yes

  • 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.

It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

380,928 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Jan 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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random CLSID} = %Application Data%\{random folder found}\{filename found in %System%}

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • {BLOCKED}jhh3b.wguards.cc

NOTES:

It drops a copy of itself in random folders or subfolders found in the %Application Data% folder. It uses the filename of a file found in the %System% folder. For example, %Application Data%\Microsoft\fontview.exe.

  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 the registry entry with an unknown data 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
    • {random CLSID} = %Application Data%\{random folder found}\{filename found in %System%}

Step 4

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