Analysis by: Jennifer Gumban
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

  TECHNICAL DETAILS

File Size: 57,250 bytes
File Type: Other
Memory Resident: No
Initial Samples Received Date: 22 Apr 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 file(s)/component(s):

  • %User Temp%\w17zsvv3.kyrlh1x5 - contains key. malware terminates if found, it means it is alread installed in infected system.
  • %User Temp%\1vaxoga5.uljo6ecr - pgp public key block
  • %User Temp%\fgechq7q.gd2rovxj - key info
  • %User Temp%\dy81okku.05xs17v6 - system info and encryption stats
  • %User Temp%\e01wvje4.s6z8jxle - contains commands that creates "hwi8xahf.cmd"
  • %User Temp%\iwzrebq5.3qurge4r - list of files
  • %User Temp%\beo8gqhe.vbs - deletes shadow copies
  • %User Temp%\m2s7qmqm.js - executes tw330u88.cmd
  • %User Temp%\tw330u88.cmd - executes beo8gqhe.vbs
  • %User Temp%\186801528.js
  • %User Temp%\foekyxta.4jmw84bs - filtered list of files
  • %User Temp%\m3mvqfy3.hoeef5tj - gpg encryption commands
  • %User Temp%\1taz5fz4.ljivo2vk - filtered list of files
  • %User Temp%\hwi8xahf.cmd - gpg encryption commands
  • %User Temp%\wdg7mu6r.vbs - uploads stats, requires parameters

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

File Infection

This Trojan avoids infecting files that contain the following strings in their names:

  • windows
  • recycle
  • program
  • avatar
  • roaming
  • msoffice
  • temporary
  • sample
  • themes
  • uploads
  • csize
  • resource
  • internet
  • com_
  • intel
  • common
  • resources
  • texture
  • profiles
  • library
  • clipart
  • manual
  • games
  • framework64
  • setupcache
  • autograph
  • maps
  • amd64
  • cache
  • support
  • guide
  • abbyy
  • application
  • thumbnails
  • avatars
  • template
  • adobe
  • AppData
  • APPDATA
  • appdata
  • temp
  • TEMP
  • Temp

Other Details

This Trojan encrypts files with the following extensions:

  • *.xls
  • *.doc
  • *.xlsx
  • *.docx
  • *.pdf
  • *.rtf
  • *.cdr
  • *.psd
  • *.dwg
  • *.cd
  • *.mdb
  • *.1cd
  • *.dbf
  • *.sqlite
  • *.jpg
  • *.zip

It renames encrypted files using the following names:

  • {original file name}.xort

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.488.07
FIRST VSAPI PATTERN DATE: 25 Apr 2016
VSAPI OPR PATTERN File: 12.489.00
VSAPI OPR PATTERN Date: 26 Apr 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

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.  
  • %User Temp%\w17zsvv3.kyrlh1x5
  • %User Temp%\1vaxoga5.uljo6ecr
  • %User Temp%\fgechq7q.gd2rovxj
  • %User Temp%\dy81okku.05xs17v6
  • %User Temp%\e01wvje4.s6z8jxle
  • %User Temp%\iwzrebq5.3qurge4r
  • %User Temp%\beo8gqhe.vbs
  • %User Temp%\m2s7qmqm.js
  • %User Temp%\tw330u88.cmd
  • %User Temp%\186801528.js
  • %User Temp%\foekyxta.4jmw84bs
  • %User Temp%\m3mvqfy3.hoeef5tj
  • %User Temp%\1taz5fz4.ljivo2vk
  • %User Temp%\hwi8xahf.cmd
  • %User Temp%\wdg7mu6r.vbs

Step 4

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


*Note: 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 5

Restore encrypted files from backup.


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