Analysis by: Jennifer Gumban
ALIASES:

W32/Kryptik.FHDI!tr (Fortinet), Ransom:Win32/Locky.D (Microsoft), Trojan-Ransom.Win32.Locky.cgs (Kaspersky)

 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. It may be dropped by other malware.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 212,992 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 30 Sep 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.

It may be dropped by the following malware:

  • W2KM_LOCKY.DLDVFT

It may be downloaded from the following remote sites:

  • https://{BLOCKED}n.ru/021ygs7

Installation

This Trojan drops the following files:

  • {folder of encrypted files}\_{number of folders encrypted}_HOWDO_text.html - ransom note

It drops and executes the following files:

  • %desktop%\_HOWDO_text.html - Ransom note
  • %desktop%\_HOWDO_text.bmp - image used as wallpaper

Other System Modifications

This Trojan modifies the following file(s):

  • It encrypts files in fixed, removable, RAM disk drives, and network shares.

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = "0"

(Note: The default value data of the said registry entry is {user preference}.)

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = "0"

(Note: The default value data of the said registry entry is {user preference}.)

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%Desktop%\_HOWDO_text.bmp"

(Note: The default value data of the said registry entry is {user preference}.)

Other Details

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

  • http://{Domain Generated Algorithm}.{org, pw, work, biz, xyz, info}/apache_handler.php
  • http://{BLOCKED}.{BLOCKED}.83.45/apache_handler.php
  • http://{BLOCKED}.{BLOCKED}.14.93/apache_handler.php
  • http://{BLOCKED}.{BLOCKED}.52.215/apache_handler.php

It encrypts files with the following extensions:

  • .001
  • .002
  • .003
  • .004
  • .005
  • .006
  • .007
  • .008
  • .009
  • .010
  • .011
  • .123
  • .3dm
  • .3ds
  • .3g2
  • .3gp
  • .602
  • .7z
  • .ARC
  • .CSV
  • .DOC
  • .DOT
  • .MYD
  • .MYI
  • .NEF
  • .PAQ
  • .PPT
  • .RTF
  • .SQLITE3
  • .SQLITEDB
  • .XLS
  • .aes
  • .apk
  • .asc
  • .asf
  • .asm
  • .asp
  • .asset
  • .avi
  • .bak
  • .bat
  • .bik
  • .bmp
  • .brd
  • .bsa
  • .bz2
  • .c
  • .cgm
  • .class
  • .cmd
  • .cpp
  • .crt
  • .cs
  • .csr
  • .d3dbsp
  • .das
  • .db
  • .dbf
  • .dch
  • .dif
  • .dip
  • .djv
  • .djvu
  • .docb
  • .docm
  • .docx
  • .dotm
  • .dotx
  • .fla
  • .flv
  • .forge
  • .frm
  • .gif
  • .gpg
  • .gz
  • .h
  • .hwp
  • .ibd
  • .iwi
  • .jar
  • .java
  • .jpeg
  • .jpg
  • .js
  • .key
  • .lay
  • .lay6
  • .lbf
  • .ldf
  • .litemod
  • .litesql
  • .ltx
  • .m3u
  • .m4a
  • .m4u
  • .max
  • .mdb
  • .mdf
  • .mid
  • .mkv
  • .mml
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .ms11
  • .ms11 (Security copy)
  • .n64
  • .odb
  • .odg
  • .odp
  • .ods
  • .odt
  • .onetoc2
  • .otg
  • .otp
  • .ots
  • .ott
  • .p12
  • .pas
  • .pdf
  • .pem
  • .php
  • .pl
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .pptm
  • .pptx
  • .psd
  • .pst
  • .qcow2
  • .rar
  • .raw
  • .rb
  • .re4
  • .sav
  • .sch
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .sql
  • .stc
  • .std
  • .sti
  • .stw
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tbk
  • .tgz
  • .tif
  • .tiff
  • .txt
  • .uop
  • .uot
  • .upk
  • .vb
  • .vbs
  • .vdi
  • .vmdk
  • .vmx
  • .vob
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .xlc
  • .xlm
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .zip
  • .wallet
  • .wallet.dat

It renames encrypted files using the following names:

  • {unique ID per victim}-{identifier}.odin

It does the following:

  • It prevents encrypting files containing any of the strings in its full path name:
    • winnt
    • Application Data
    • AppData
    • Program Files (x86)
    • Program Files
    • thumbs.db
    • $Recycle.Bin
    • System Volume Information
    • Windows
  • It deletes shadow copies by executing the following command:
    • vssadmin.exe Delete Shadows /Quiet /All

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.808.03
FIRST VSAPI PATTERN DATE: 30 Sep 2016
VSAPI OPR PATTERN File: 12.809.00
VSAPI OPR PATTERN Date: 01 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

Remove the malware/grayware file dropped/downloaded by Ransom_LOCKY.NIDO. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     W2KM_LOCKY.DLDVFT

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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.
{folder of encrypted files}\_{number of folders encrypted}_HOWDO_text.html
%Desktop%\_HOWDO_text.html
%Desktop%\_HOWDO_text.bmp

Step 6

Reset your Desktop properties

[ Learn More ]

Step 7

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