TROJ_CRYPLOCK

 Analysis by: Rika Joi Gregorio

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

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 connects to certain websites to send and receive information.

  TECHNICAL DETAILS

Memory Resident:

Yes

Payload:

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

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 copies of itself into the affected system:

  • %All Users Profile%\Application Data\{random folder name}\01000000
  • %Windows%\{random 8 letters}.exe

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It drops the following file(s)/component(s):

  • %All Users Profile%\Application Data\{random folder name}\00000000
  • %All Users Profile%\Application Data\{random folder name}\02000000
  • %All Users Profile%\Application Data\{random folder name}\03000000 - copy of ransom note
  • %All Users Profile%\Application Data\{random folder name}\04000000

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 processes:

  • explorer.exe

It creates the following folders:

  • %All Users Profile%\Application Data\{random folder name}

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 injects codes into the following process(es):

  • created explorer.exe

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
{random 8 letters} = "%Windows%\{random 8 letters}.exe"

Information Theft

This Trojan gathers the following data:

  • Machine GUID
  • Computer name

Other Details

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

  • js-static.ru:443/topic.php

It encrypts files with the following extensions:

  • 3ds
  • 3fr
  • 3pr
  • 7z
  • ab4
  • ac2
  • accdb
  • accde
  • accdr
  • accdt
  • acr
  • adb
  • agd1
  • ai
  • ait
  • al
  • apj
  • arw
  • asm
  • asp
  • awg
  • backup
  • backupdb
  • bak
  • bdb
  • bgt
  • bik
  • bkp
  • blend
  • bpw
  • cdf
  • cdr
  • cdr3
  • cdr4
  • cdr5
  • cdr6
  • cdrw
  • cdx
  • ce1
  • ce2
  • cer
  • cfp
  • cgm
  • cib
  • cls
  • cmt
  • cpi
  • cpp
  • cr2
  • craw
  • crt
  • crw
  • csh
  • csl
  • css
  • csv
  • dac
  • db
  • db-journal
  • db3
  • dbf
  • dc2
  • dcr
  • dcs
  • ddd
  • ddoc
  • ddrw
  • der
  • design
  • dgc
  • djvu
  • dng
  • doc
  • docm
  • docx
  • dot
  • dotm
  • dotx
  • drf
  • drw
  • dwg
  • dxb
  • erbsql
  • erf
  • exf
  • fdb
  • ffd
  • fff
  • fh
  • fhd
  • fpx
  • fxg
  • gray
  • grey
  • gry
  • hbk
  • hpp
  • ibank
  • ibd
  • ibz
  • idx
  • iiq
  • incpas
  • jpeg
  • jpg
  • js
  • kc2
  • kdbx
  • kdc
  • kpdx
  • lua
  • mdb
  • mdc
  • mef
  • mfw
  • mmw
  • moneywell
  • mos
  • mpg
  • mrw
  • myd
  • ndd
  • nef
  • nop
  • nrw
  • ns2
  • ns3
  • ns4
  • nsd
  • nsf
  • nsg
  • nsh
  • nwb
  • nx1
  • nx2
  • nyf
  • odb
  • odf
  • odg
  • odm
  • odp
  • ods
  • odt
  • orf
  • otg
  • oth
  • otp
  • ots
  • ott
  • p12
  • p7b
  • p7c
  • pat
  • pcd
  • pdf
  • pef
  • pem
  • pfx
  • php
  • pl
  • pot
  • potm
  • potx
  • ppam
  • pps
  • ppsm
  • ppsx
  • ppt
  • pptm
  • pptx
  • ps
  • psafe3
  • psd
  • ptx
  • py
  • ra2
  • raf
  • rar
  • raw
  • rdb
  • rtf
  • rw2
  • rwl
  • rwz
  • s3db
  • sas7bdat
  • sav
  • sd0
  • sd1
  • sda
  • sdf
  • sldm
  • sldx
  • sql
  • sqlite
  • sqlite3
  • sqlitedb
  • sr2
  • srf
  • srw
  • st4
  • st5
  • st6
  • st7
  • st8
  • stc
  • std
  • sti
  • stw
  • stx
  • sxc
  • sxd
  • sxg
  • sxi
  • sxm
  • sxw
  • txt
  • wb2
  • x3f
  • xla
  • xlam
  • xll
  • xlm
  • xls
  • xlsb
  • xlsm
  • xlsx
  • xlt
  • xltm
  • xltx
  • xlw
  • xml
  • ycbcra
  • zip

It renames encrypted files using the following names:

  • {original file name and extension}.encrypted

NOTES:

It drops the ransom note, DECRYPT_INSTRUCTIONS.html, to every directory it encrypts.

It deletes shadow copies by executing the following command:

  • vssadmin.exe Delete Shadows /All /Quiet

It displays the following ransom message: