TROJ_CRYPLOCK.FC

 Analysis by: Jaime Benigno Reyes

 ALIASES:

Ransom:Win32/Teerac.A (Microsoft); Win32/Filecoder.DI trojan (Nod32)

 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:

Downloaded from the Internet, Dropped by other malware


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 downloaded by other malware/grayware from remote sites.

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

470,016 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Oct 2014

Payload:

Encrypts files, Connects to URLs/IPs

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 downloaded by the following malware/grayware from remote sites:

It may be downloaded from the following remote site(s):

  • http://{BLOCKED}dcenter.ru/dbanner.png

Installation

This Trojan 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 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 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:

  • {BLOCKED}tic.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

However, as of this writing, the said sites are inaccessible.

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

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.202.03

FIRST VSAPI PATTERN DATE:

10 Oct 2014

VSAPI OPR PATTERN File:

11.203.00

VSAPI OPR PATTERN Date:

11 Oct 2014

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 malware/grayware files that dropped/downloaded TROJ_CRYPLOCK.FC. (Note: Please skip this step if the threats listed below have already been removed.)

Step 4

Scan your computer with your Trend Micro product and note files detected as TROJ_CRYPLOCK.FC

Step 5

Restart in Safe Mode

[ Learn More ]

Step 6

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

Step 7

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

Step 8

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.
  • DECRYPT_INSTRUCTIONS.html

Step 9

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

NOTES:

Restore the encrypted files from backup. Note that the encrypted files have the extension .encrypted.


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