Modified by: RonJay Kristoffer Caragay
ALIASES:

Trojan:Win32/Crilock (Microsoft); Trojan-Ransom.Win32.Blocker.enwh(Kasperksy); Trojan.Cryptolocker(Norton); Trojan.Win32.Crilock(Ikarus)

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

Tamaño del archivo 815,104 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 19 May 2014

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:

  • %AppDataLocal%\{random filename}.exe

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local 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 = "%AppDataLocal%\{random filename}.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
*CryptoLocker = "%AppDataLocal%\{random filename}.exe"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\CryptoLocker_0388
VersionInfo = "{hex values}"

HKEY_CURRENT_USER\Software\CryptoLocker_0388
PublicKey = "{hex values}"

HKEY_CURRENT_USER\Software\CryptoLocker_0388
Wallpaper = "{hex values}"

HKEY_CURRENT_USER\Software\CryptoLocker_0388\
Files
{path and filename of encrypted files} = "{hex values}"

HKEY_CLASSES_ROOT\{random characters}\shell\
open\command
(Default) = ""%AppDataLocal%\{random filename.exe}" - "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
{random characters}\shell\open\
command
(Default) = ""%AppDataLocal%\{random filename.exe}" - "%1" %*"

Dropping Routine

This Trojan drops the following files:

  • %Desktop%\{random filename}.bmp

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {random character}.ru
  • {random character}.info
  • {random character}.co.uk
  • {random character}.biz
  • {random character}.org
  • {random character}.com
  • {random character}.net

It deletes itself after execution.