Analysis by: John Kevin Sanchez
ALIASES:

Trojan-Ransom.Win32.Crypmodadv.xda (Kaspersky), Ransomer.MFA (AVG), Win32.Trojan.Raas.Auto (Tencent)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, 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 is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size: 26,624 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 24 Oct 2016
Payload: Encrypts 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 the following files:

  • %Application Data%\Microsoft\work.now
  • %Application Data%\Microsoft\request.dat - contains request code
  • %Application Data%\Microsoft\encrypted.dat
  • %Desktop%\ИНСТРУКЦИЯ INSTRUCTION.txt - ransom note

(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.. %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 encrypts files with the following extensions:

  • .txt
  • .pdf
  • .html
  • .rtf
  • .avi
  • .mov
  • .mp4
  • .amr
  • .mp3
  • .ogg
  • .dwg
  • .cdw
  • .max
  • .psd
  • .3dm
  • .3ds
  • .ps
  • .ai
  • .svg
  • .indd
  • .cpp
  • .pas
  • .php
  • .cs
  • .py
  • .java
  • .fla
  • .pl
  • .sh
  • .jpg
  • .jpeg
  • .jps
  • .bmp
  • .tiff
  • .png
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .accdb
  • .odt
  • .odp
  • .odx
  • .db
  • .dbf
  • .mdf
  • .sdf
  • .mdb
  • .sql
  • .rar
  • .7z
  • .zip
  • .jar
  • .vcf
  • .cer
  • .csr
  • .torrent
  • .report
  • .key
  • .csv
  • .xml

It renames encrypted files using the following names:

  • {filename}.lock93

It does the following:

  • It avoids encrypting files in folders/directories containing the following strings:
    Windows
    PerfLogs
    msocache
    \Users\Default
    \Users\Default User
    \Users\Public
    \Users\All Users
    \Users\Все пользователи
    ProgramData
    AppData
    Program Files
    Program Files (x86)
  • It encrypts files in all fixed and removable drives.

It is capable of encrypting files in the affected system.

NOTES:
This ransomware displays the following images:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.860.04
FIRST VSAPI PATTERN DATE: 26 Oct 2016
VSAPI OPR PATTERN File: 12.861.00
VSAPI OPR PATTERN Date: 27 Oct 2016

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

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Application Data%\Microsoft\work.now
  • %Application Data%\Microsoft\request.dat
  • %Application Data%\Microsoft\encrypted.dat
  • %Desktop%\ИНСТРУКЦИЯ INSTRUCTION.txt

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_LOCK93.A. 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.

Step 6

Restore encrypted files from backup.


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