RANSOM_LOCKY.KCL

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 does not have any propagation routine.

It does not have any backdoor routine.

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

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 files:

• %Desktop%\_HELP_instructions.txt - ransom note
• %Desktop%\_HELP_instructions.bmp - image used as wallpaper
• {folders containing encrypted files}\_HELP_instructions.txt - ransom note

(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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:

• %User Temp%\svchost.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

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
Locky = "%User Temp%\svchost.exe"

Other System Modifications

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

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

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

HKEY_CURRENT_USER\Software\{random characters}

It sets the system's desktop wallpaper to the following image:

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Other Details

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

• http://{BLOCKED}.{BLOCKED}.154.126/main.php
• http://{BLOCKED}.{BLOCKED}.170.244/main.php
• http://{BLOCKED}.{BLOCKED}.87.106/main.php
• {Domain Generated Algorithm}.{ru, info, biz, work, pl ,org, pw, xyz}

  It sends the following information in encrypted form:
  id={victim ID}&act={getkey, gettext, stats}&affid={affiliate ID}&lang={computer language}&corp={value}&serv={value}&os={operating system}&sp={service pack}&x64={0,1}

It encrypts files with the following extensions:

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

It does the following:

• It prevents to encrypt files containing any of the strings in its full pathname:
  • AppData
  • Application Data
  • Program Files
  • Program Files (x86)
  • $Recycle.Bin
  • System Volume Information
  • Windows
  • winnt
  • BOOT
  • temp
  • thumbs.db
  • _HELP_instructions.bmp
  • _HELP_instructions.txt
  • _Locky_recover_instructions.bmp
  • _Locky_recover_instructions.txt
• After encryption of files, it uninstalls itself by deleting its autorun registry and its copy.

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

It gathers the following information and reports it to its servers:

• Language of affected system
• number of failed encrypted files
• number of encrypted files
• OS architecture (if 64bit)
• victim ID

NOTES:

This ransomware encrypts files in fixed, removable, RAM disk drives, and network shares. It renames the encrypted files to {unique ID per victim}{identifier}.locky.