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RANSOM_CRYPTOR.C

January 19, 2016
 Analysis by: David John Agni
 ALIASES:

Trojan.Linux.Encoder.A (BitDefender), Linux/Filecoder.D (ESET-NOD32),

 PLATFORM:

Unix, Linux

 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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

257263 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

15 Jan 2015

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 non-malicious files:

  • README_FOR_DECRYPT.txt - to all folders where files are encrypted.

Other Details

This Trojan encrypts files with the following extensions:

  • .php
  • .html
  • .tar
  • .gz
  • .sql
  • .js
  • .css
  • .pdf
  • .tgz
  • .war
  • .jar
  • .java
  • .class
  • .ruby
  • .rar
  • .zip
  • .db
  • .7z
  • .doc
  • .pdf
  • .xls
  • .properties
  • .xml
  • .jpg
  • .jpeg
  • .png
  • .gif
  • .mov
  • .avi
  • .wmv
  • .mp3
  • .mp4
  • .wma
  • .aac
  • .wav
  • .pem
  • .pub
  • .docx
  • .apk
  • .exe
  • .dll
  • .tpl
  • .psd
  • .asp
  • .phtml
  • .aspx
  • .csv

It opens the following files:

  • ./readme.crypto - Contains data to be written in README_FOR_DECRYPT.txt
  • ./index.crypto

It renames encrypted files using the following names:

  • {Filename}.encrypted

It deletes the initially executed copy of itself

NOTES:

This Trojan initially encrypts files found in the following folders:

  • /etc/apache2
  • /etc/nginx
  • /home
  • /root
  • /var/lib/mysql
  • /var/log
  • /var/www

It avoids encrypting files in the following folders:

  • /root/.ssh
  • /usr/bin
  • /etc/ssh

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.275.00

VSAPI OPR PATTERN Date:

16 Jan 2016

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYPTOR.C. 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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