RANSOM_CRYPTESLA.CBQ163I

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

Ransom.TeslaCrypt (Malwarebytes); Ransom:Win32/Tescrypt.Q (Microsoft); Trojan/Win32.Teslacrypt; Trojan/Win32.Teslacrypt (AhnLab-V3)

 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.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size:

423,779 bytes

File Type:

EXE

Initial Samples Received Date:

18 Mar 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:

  • %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 7.)

It drops the following file(s)/component(s):

  • %Desktop%\RECOVER{random letters}.html
  • %Desktop%\RECOVER{random letters}.png
  • %Desktop%\RECOVER{random letters}.txt
  • {folders containing encrypted files}RECOVER{random letters}.png
  • {folders containing encrypted files}RECOVER{random letters}.txt
  • {folders containing encrypted files}RECOVER{random letters}.html
  • %My Documents%\recover_file.txt

    (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 7.)

(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.)

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
svc-{random characters} = "%System%\cmd /C start "" "%My Documents%\{random filename}.exe""

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\trueimg
ID = "{ID}"

HKEY_CURRENT_USER\Software\{ID}
data = "{random values}"

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

HKEY_CURRENT_USER\Software\trueimg

HKEY_CURRENT_USER\Software\{ID}

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}k.com/phsys.php
  • http://{BLOCKED}e.net/phsys.php
  • http://{BLOCKED}oherbal.com/phsys.php
  • http://{BLOCKED}tion.info/plugins/phsys.php
  • http://{BLOCKED}senseprotection.com/phsys.php
  • http://{BLOCKED}toreforyou.com/phsys.php

It is capable of encrypting files in the affected system.

  SOLUTION

Minimum Scan Engine:

9.800

NOTES:

Trend customers:

    Keep your pattern and scan engine files updated. Trend Micro antivirus software can clean or remove most types of computer threats. Malware, though, such as Trojans, scripts, overwriting viruses and joke programs which are identified as uncleanable, should simply be deleted.

All Internet users:

  • Use HouseCall - the Trend Micro online threat scanner to check for malware that may already be on your PC.
  • Catch malware/grayware before they affect your PC or network. Secure your Web world with Trend Micro products that offer the best anti-threat and content security solutions for home users, corporate users, and ISPs. Go here for more information on Trend Micro products that fit your needs.


Did this description help? Tell us how we did.