RANSOM_CRYPTESLA.SMK3

April 09, 2016
 Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

 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:

290816 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Apr 2016

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%\BitLockerWizard.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following files:

  • %User Profile%\Documents\+recover+file.txt
  • %User Profile%\Documents\data_storage

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} 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
{Random Characters} = "%System%\CMD.EXE /C START "" "%Application Data%\BitLockerWizard.exe""

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}l.org/wp-content/plugins/js_composer/assets/lib/font-awesome/src/assets/font-awesome/fonts/stringfile.php
  • http://{BLOCKED}mbargada.com/wp-content/plugins/formcraft/php
  • http://{BLOCKED}ersan.com.tr/wp-content/plugins/contact-form-maker/images/02/03/stringfile.php
  • http://forms.{BLOCKED}t.in/cgi-bin/stringfile.php
  • http://kknk-shop.dev.{BLOCKED}igital.com/stringfile.php
  • http://naturstein-{BLOCKED}rt.de/modules/mod_cmscore/stringfile.php

NOTES:

This ransomware drops the following whenever it is able to encyrpt:

  • {RecOveR}-{random characters}.Htm
  • {RecOveR}-{random characters}.Png
  • {RecOveR}-{random characters}.Txt