TROJ_CRILOCK.ITR

 Analysis by: Anthony Joe Melgarejo

 ALIASES:

Trojan:Win32/Crilock.A (Microsoft), Trojan.Ransomcrypt.F (Symantec), Ransom-O (McAfee), W32/Blocker.CJQD!tr (Fortinet), Trojan-Ransom.Win32.Blocker (Ikarus), Win32/Filecoder.BQ trojan (ESET)

 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:
 INFORMATION EXPOSURE:

  • 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:

703,488 bytes

File Type:

EXE

Initial Samples Received Date:

27 Sep 2013

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.

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %Application Data%\{random file name}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
CryptoLocker = "%Application Data%\{random file name}.exe"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {pseudorandom domain}.biz
  • {pseudorandom domain}.ru
  • {pseudorandom domain}.net
  • {pseudorandom domain}.info
  • {pseudorandom domain}.co.uk
  • {pseudorandom domain}.com
  • {pseudorandom domain}.org