RANSOM_CRYPTESLA.CBQ163V

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.

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:

• %My Documents%\{random filename}.exe

  (Note: %My Documents% is usually C:\Documents and Settings\{user name}\My Documents on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Documents on Windows Vista and above.)

It drops the following files:

• {folders containing encrypted files}\+REcovER+{random characters}+.txt
• {folders containing encrypted files}\+REcovER+{random characters}+.html
• {folders containing encrypted files}\+REcovER+{random characters}+.png
• %My Documents%\+REcovER+{random characters}+.txt
• %My Documents%\+REcovER+{random characters}+.html
• %My Documents%\+REcovER+{random characters}+.png
• %My Documents%\recover.bin
• %My Documents%\+recover+file.txt

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 key name} = "C:\WINDOWS\SYSTEM32\CMD.EXE /C START "" "%My Documents%\{random filename}.exe"

Other System Modifications

This Trojan modifies the following file(s):

• It encrypts files in all fixed, removable, and network drives and shares.
• It does not append an extension name to the encrypted files

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLinkedConnections = "1"

Other Details

This Trojan connects to the following possibly malicious URL:

• http://{BLOCKED}mbargada.com/wp-content/plugins/formcraft/php/swift/lib/classes/Swift/Mime/HeaderEncoder/stringfile.php
• http://{BLOCKED}l.org/wp-content/plugins/js_composer/assets/lib/font-awesome/src/assets/font-awesome/fonts/stringfile.php
• http://{BLOCKED}s.net.in/cgi-bin/stringfile.php
• http://kknk-shop.dev{BLOCKED}igital.com/stringfile.php
• http://{BLOCKED}ersan.com.tr/wp-content/plugins/contact-form-maker/images/02/03/stringfile.php
• http://{BLOCKED}ein-schubert.de/modules/mod_cmscore/stringfile.php