Analysis by: Julie Anne Cabuhat
ALIASES:

Ransom.VirLock (Malwarebytes), Gen:Variant.Ransom.VxLock.1 (F-Secure )

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes


  TECHNICAL DETAILS

Tamaño del archivo 19,456 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 26 Jan 2017
Carga útil Encrypts files

Installation

This Trojan adds the following mutexes to ensure that only one of its copies runs at any one time:

  • VXLOCK32_64

Other Details

This Trojan encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .sqlite
  • .odt
  • .jpg
  • .gif
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .xsd
  • .cpp
  • .h
  • .htm
  • .py
  • .reg

It requires the existence of the following files to properly run:

  • {malware path}\RSA_keys.pub
  • {malware path}\RSA_keys.private

It renames encrypted files using the following names:

  • {Original filename and extension}.vxLock

It does the following:

  • It checks if the following module is loaded in its process as an anti-sandbox technique:
    • SbieDLL.dll
  • It uses various APIs as an anti-debugging technique.

NOTES:

The ransomware encrypts files in the following location:

  • %Desktop%

    •   SOLUTION

    Motor de exploración mínimo 9.850
    Primer archivo de patrones de VSAPI 13.184.00
    Primera fecha de publicación de patrones de VSAPI 26 Jan 2017
    Versión de patrones OPR de VSAPI 13.185.00
    Fecha de publicación de patrones OPR de VSAPI 27 Jan 2017

    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

    Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

    Step 3

    Restore encrypted files from backup.

    Step 4

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


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