Ransom.Python.PYLOCKY.B

 Analysis by: John Rey Canon

 ALIASES:

Python/Filecoder_Locky.B!tr (Fortinet); Trojan-Ransom.Locky (Ikarus); Trojan:Win32/Occamy.B (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Spammed via email, Dropped by other malware, Downloaded from the Internet

This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It creates folders where it drops its files.

It connects to certain websites to send and receive information. It is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

5,524,987 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Sep 2018

Payload:

Connects to URLs/IPs, Steals information, Displays message/message boxes, Encrypts files

Arrival Details

This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 Ransomware drops and executes the following files:

  • %User Temp%\is-{Random Folder Name 1}.tmp\{Malware Name}.tmp
  • %User Temp%\is-{Random Folder Name 2}.tmp\lockyfud.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

It creates the following folders:

  • %User Temp%\is-{Random Folder Name 1}.tmp\
  • %User Temp%\is-{Random Folder Name 2}.tmp\
  • %User Temp%\tmp4x_gld\gen_py\

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run\
MyProgram
MyProgram = %User Temp%\is-{Random Folder Name 2}.tmp\lockyfud.exe

Information Theft

This Ransomware gathers the following data:

  • Computer Name
  • Username
  • Processor Information
  • GPU Information
  • OS Version
  • RAM Information
  • Computer Language
  • MAC Address

Other Details

This Ransomware connects to the following website to send and receive information:

  • http://{BLOCKED}yrkumqih5l.onion/index.php

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • 3dm
  • 3ds
  • 3g2
  • 3gp
  • 7z
  • accdb
  • ai
  • aif
  • apk
  • app
  • asf
  • asp
  • aspx
  • avi
  • bak
  • bat
  • bmp
  • c
  • cbr
  • cer
  • cfg
  • cfm
  • cgi
  • class
  • com
  • cpp
  • cs
  • css
  • csv
  • dat
  • db
  • dbf
  • dds
  • deb
  • dem
  • dif
  • doc
  • docm
  • docx
  • dotm
  • dotx
  • eps
  • flv
  • fnt
  • fon
  • fpx
  • gam
  • ged
  • gif
  • gz
  • h
  • htm
  • html
  • ics
  • iff
  • indd
  • ini
  • iso
  • j2c
  • j2k
  • java
  • jfif
  • jif
  • jp2
  • jpeg
  • jpg
  • jpx
  • js
  • json
  • jsp
  • key
  • keychain
  • log
  • lua
  • m3u
  • m4a
  • m4v
  • max
  • mdb
  • mht
  • mhtml
  • mid
  • mkv
  • mov
  • mp3
  • mp4
  • mpa
  • mpg
  • msg
  • msi
  • nes
  • obj
  • ods
  • odt
  • old
  • otf
  • pages
  • pcd
  • pct
  • pdf
  • php
  • pkg
  • pl
  • png
  • pps
  • ppt
  • pptx
  • prf
  • prn
  • ps
  • psd
  • py
  • rar
  • rm
  • rom
  • rpm
  • rss
  • rtf
  • sav
  • sdf
  • sh
  • slk
  • sln
  • sql
  • srt
  • svg
  • swf
  • swift
  • tar
  • tex
  • tga
  • tgz
  • thm
  • tif
  • tiff
  • tmp
  • torrent
  • ttf
  • txt
  • vb
  • vcf
  • vcxproj
  • vob
  • wav
  • wma
  • wmv
  • wpd
  • wps
  • xhtml
  • xla
  • xlam
  • xls
  • xlsb
  • xlsm
  • xlsx
  • xltx
  • xml
  • xps
  • yuv
  • zip
  • zipx

It appends the following extension to the file name of the encrypted files:

  • .lockedfile

It drops the following file(s) as ransom note:

  • {Encrypted Directory}\LOCKY-README.txt


  • {Encrypted Directory}\{Original Filename}.lockymap

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.482.07

FIRST VSAPI PATTERN DATE:

03 Sep 2018

VSAPI OPR PATTERN File:

14.483.00

VSAPI OPR PATTERN Date:

04 Sep 2018

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

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\MyProgram
    • %User Temp%\is-{Random Folder Name 2}.tmp\lockyfud.exe

Step 5

Search and delete this file

[ 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.
  • {Encrypted Directory}\LOCKY-README.txt
  • {Encrypted Directory}\{Original Filename}.lockymap
  • %User Temp%\is-{Random Folder Name 1}.tmp\{Malware Name}.tmp
  • %User Temp%\is-{Random Folder Name 2}.tmp\lockyfud.exe

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\is-{Random Folder Name 1}.tmp
  • %User Temp%\is-{Random Folder Name 2}.tmp
  • %User Temp%\tmp4x_gld\gen_py

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Python.PYLOCKY.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.

Step 8

Restore encrypted files from backup.


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