TROJ_CRILOCK.EU

 Analysis by: RonJay Kristoffer Caragay

 ALIASES:

Trojan-Ransom.Win32.Blocker.enfi(Kaspersky), Trojan horse Crypt3.MEK(AVG), a variant of Win32/Kryptik.CATY trojan(NOD32)

 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:
 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:

796,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Apr 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 and executes them:

  • %AppDataLocal%\{random file name}.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\RunOnce
*CryptoLocker = "%AppDataLocal%\{random file name}.exe"

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • {random character}.ru
  • {random character}.biz
  • {random character}.co.uk
  • {random character}.info
  • {random character}.org
  • {random character}.com
  • {random character}.net
  • {random character}.info
  • ns2-jiruduglobal-ns.com

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.762.01

FIRST VSAPI PATTERN DATE:

28 Apr 2014

VSAPI OPR PATTERN File:

10.763.00

VSAPI OPR PATTERN Date:

30 Apr 2014

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

Scan your computer with your Trend Micro product and note files detected as TROJ_CRILOCK.EU

Step 3

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • *CryptoLocker = "%AppDataLocal%\{random file name}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • CryptoLocker = "%AppDataLocal%\{random file name}.exe"

Step 5

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


Did this description help? Tell us how we did.