Analysis by: Ryan Gardo

ALIASES:

Downloader.Banload2.ZOM(AVG); Artemis!1674EA64057D(McAfee); Trojan.Cryptolocker.E(Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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 a website to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 762,368 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 24 Mar 2015

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:

  • %WINDOWS%\{random filename}.exe

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

  • %All Users Profile%\%Application Data%\{random folder name}\03000000 ← encrypted copy of ransom note
  • %All Users Profile%\%Application Data%\{random folder name}\04000000
  • %All Users Profile%\%Application Data%\{random folder name}\01000000 - encrypted copy of itself
  • %All Users Profile%\%Application Data%\{random folder name}\02000000
  • %All Users Profile%\%Application Data%\{random folder name}\00000000

(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 processes:

  • explorer.exe

It injects codes into the following process(es):

  • added explorer.exe

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random letters} = "%Windows%\{random filename}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter

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

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV9 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV8 = "0"

Backdoor Routine

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

  • http://{BLOCKED}raje.ru/topic.php

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

Information Theft

This Trojan gathers the following data:

  • Machine GUID
  • Computer name

Other Details

This Trojan encrypts files with the following extensions:

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

It renames encrypted files using the following names:

  • {original file name and extension}.encrypted

NOTES:
It does not proceed to its intended encryption routine since its C&C server is no longer accessible.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.558.06
FIRST VSAPI PATTERN DATE: 24 Mar 2015
VSAPI OPR PATTERN File: 11.559.00
VSAPI OPR PATTERN Date: 25 Mar 2015

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

Restart in Safe Mode

[ Learn More ]

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random letters} = "%WINDOWS%\{random filename}.exe"

Step 5

Delete this registry key

[ Learn More ]

=Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter

Step 6

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.
  • %All Users Profile%\%Application Data%\{random folder name}\00000000
  • %All Users Profile%\%Application Data%\{random folder name}\01000000
  • %All Users Profile%\%Application Data%\{random folder name}\02000000
  • %All Users Profile%\%Application Data%\{random folder name}\03000000
  • %All Users Profile%\%Application Data%\{random folder name}\04000000
  • DECRYPT_INSTRUCTIONS.html

Step 7

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

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


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