Analysis by: Jeanne Jocson
ALIASES:

Ransom:Win32/Tescrypt.A(Microsoft), Win32/Kryptik.EQVX(ESET)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Canal de infección Downloaded from the Internet

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 the initially executed copy of itself.

  TECHNICAL DETAILS

Tamaño del archivo 471,040 bytes
Tipo de archivo EXE
Fecha de recepción de las muestras iniciales 11 Mar 2016
Carga útil Connects to URLs/IPs, Displays message, Encrypts files, Drops files

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 a copy of itself in the following folders using different file names:

  • %Windows%\{random file name}.exe

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

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} = "%System%\cmd.exe /c start "" "%Windows%\{random filename}.exe""

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\zzzsys

HKEY_CURRENT_USER\Software\{Installation ID}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnabledLinkConnections = "1"

HKEY_CURRENT_USER\Software\{Installation ID}
data = {encryption information}

HKEY_CURRENT_USER\Software\zzzsys
ID = {Installation ID}

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Documents\recover_file_{random letters}.txt
  • %Desktop%\_ReCoVeRy_.TXT
  • %Desktop%\_ReCoVeRy_.HTM
  • %Desktop%\_ReCoVeRy_.png
  • {folders containing encrypted files}\_ReCoVeRy_+{random letters}.png
  • {folders containing encrypted files}\_ReCoVeRy_+{random letters}.txt
  • {folders containing encrypted files}\_ReCoVeRy_+{random letters}.html

(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.. %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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}hop.net/wcspng.php
  • http://{BLOCKED}raining.com/wp-includes/theme-compat/wcspng.php
  • http://{BLOCKED}gfeng.cn/images/lurd/wcspng.php
  • http://{BLOCKED}freaknetworks.com/dev/wp-content/uploads/2015/07/wcspng.php
  • http://{BLOCKED}randphone.com/wp-content/themes/storefront/wcspng.php
  • http://{BLOCKED}annel.com/wp-admin/maint/wcspng.php

It deletes the initially executed copy of itself