Analysis by: Jennifer Gumban
 Modified by: Cris Nowell Pantanilla

 ALIASES:

Trojan.Win32.Deshacop.daw (Kaspersky), Ransom:Win32/Crituck.A (Microsoft), Win32/Filecoder.CryptoLuck.A (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This malware is a new family of ransomware discovered on early November 2016. Users affected by this particular ransomware may find their files and documents rendered inaccessible.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may be unknowingly downloaded by a user while visiting malicious websites. It may be manually installed by a user.

It connects to certain websites to send and receive information. It terminates itself if it detects it is being run in a virtual environment.

  TECHNICAL DETAILS

Payload: Encrypts Files

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

It may be manually installed by a user.

Installation

This Trojan drops the following component file(s):

  • {path of encrypted files}\@WARNING_FILES_ARE_ENCRYPTED.{victim id}.txt ← ransom note
  • %Application Data%\76ff\crp.cfg ← configuration file
  • %Application Data%\76ff\goopdate.ini ← 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.)

It drops and executes the following files:

  • %Application Data%\76ff\GoogleUpdate.exe ← loader
  • %Application Data%\76ff\goopdate.dll ← encryptor (Ransom_CryptoLuck.A)

(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.)

It creates the following folders:

  • %Application Data%\76ff

(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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • CryptoLuck_Instance

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
GoogleUpdate.exe = "%Application Data%\76ff\GoogleUpdate.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\sosad_{victim id}

HKEY_CURRENT_USER\Software\sosad_{victim id}
conf = {config file}

HKEY_CURRENT_USER\Software\sosad_{victim id}\
files
{full filename of encrypted files} = {flag}

Other Details

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

  • http://{BLOCKED}ares.top/two/index.php

It encrypts files with the following extensions:

  • .3ds
  • .3fr
  • .4db
  • .4dd
  • .7z
  • .7zip
  • .accdb
  • .accdt
  • .aep
  • .aes
  • .ai
  • .apk
  • .arch00
  • .arj
  • .arw
  • .asset
  • .bar
  • .bay
  • .bc6
  • .bc7
  • .big
  • .bik
  • .bkf
  • .bkp
  • .blob
  • .bpw
  • .bsa
  • .cas
  • .cdr
  • .cer
  • .cfr
  • .cr2
  • .crp
  • .crt
  • .crw
  • .csv
  • .d3dbsp
  • .das
  • .dazip
  • .db0
  • .dba
  • .dbf
  • .dbx
  • .dcr
  • .der
  • .desc
  • .dmp
  • .dng
  • .doc
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dwfx
  • .dwg
  • .dwk
  • .dxf
  • .dxg
  • .eml
  • .epk
  • .eps
  • .erf
  • .esm
  • .fdb
  • .ff
  • .flv
  • .forge
  • .fos
  • .fpk
  • .fsh
  • .gdb
  • .gho
  • .gpg
  • .gxk
  • .hkdb
  • .hkx
  • .hplg
  • .hvpl
  • .ibank
  • .icxs
  • .idx
  • .ifx
  • .indd
  • .iso
  • .itdb
  • .itl
  • .itm
  • .iwd
  • .iwi
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .kdb
  • .kdbx
  • .kdc
  • .key
  • .kf
  • .ksd
  • .layout
  • .lbf
  • .litemod
  • .lrf
  • .ltx
  • .lvl
  • .m2
  • .map
  • .max
  • .mcmeta
  • .mdb
  • .mdbackup
  • .mddata
  • .mdf
  • .mef
  • .menu
  • .mlx
  • .mpd
  • .mpp
  • .mpqge
  • .mrwref
  • .msg
  • .myo
  • .nba
  • .nbf
  • .ncf
  • .nrw
  • .nsf
  • .ntl
  • .nv2
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .odt
  • .ofx
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pak
  • .pdb
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .pgp
  • .pkpass
  • .ppj
  • .pps
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prproj
  • .psd
  • .psk
  • .pst
  • .psw
  • .ptx
  • .py
  • .qba
  • .qbb
  • .qbo
  • .qbw
  • .qdf
  • .qfx
  • .qic
  • .qif
  • .r3d
  • .raf
  • .rar
  • .raw
  • .rb
  • .re4
  • .rgss3a
  • .rim
  • .rofl
  • .rtf
  • .rw2
  • .rwl
  • .saj
  • .sav
  • .sb
  • .sdc
  • .sdf
  • .sid
  • .sidd
  • .sidn
  • .sie
  • .sis
  • .sko
  • .slm
  • .snx
  • .sql
  • .sr2
  • .srf
  • .srw
  • .sum
  • .svg
  • .sxc
  • .syncdb
  • .t12
  • .t13
  • .tar
  • .tax
  • .tbl
  • .tib
  • .tor
  • .txt
  • .upk
  • .vcf
  • .vcxproj
  • .vdf
  • .vfs0
  • .vpk
  • .vpp_pc
  • .vtf
  • .w3x
  • .wallet
  • .wb2
  • .wdb
  • .wotreplay
  • .wpd
  • .wps
  • .x3f
  • .xf
  • .xlk
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xxx
  • .zip
  • .ztmp

It renames encrypted files using the following names:

  • {filename}.{victim id}_luck

It terminates itself if it detects it is being run in a virtual environment.

It does the following:

  • It deletes shadow copies by executing the following command:
      vssadmin.exe delete shadows /all /quiet

It terminates itself if windows or classes contain any of the following string(s):

  • OLLYDBG
  • VBoxTrayToolWnd
  • VBoxTrayToolWndClass
  • VMDisplayChangeControlClass
  • VMwareDragDetWndClass
  • VMwareTrayIcon
  • vmtoolsdControlWndClass

NOTES:

It changes the wallpaper of the affected system with the following image:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.902.05
FIRST VSAPI PATTERN DATE: 16 Nov 2016
VSAPI OPR PATTERN File: 12.903.00
VSAPI OPR PATTERN Date: 17 Nov 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

Identify and terminate files detected as RANSOM_CRYPTOLUCK.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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
    • GoogleUpdate.exe = "%Application Data%\76ff\GoogleUpdate.exe"

Step 4

Delete this registry key

[ 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
    • sosad_{victim id}

Step 5

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. %Application Data%\76ff

Step 6

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.
{path of encrypted files}\@WARNING_FILES_ARE_ENCRYPTED.{victim id}.txt
%Application Data%\76ff\crp.cfg
%Application Data%\76ff\goopdate.ini
%Application Data%\76ff\GoogleUpdate.exe
%Application Data%\76ff\goopdate.dll

Step 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYPTOLUCK.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 8

Restore encrypted files from backup.


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