RANSOM_LOCKY.DS

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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information. 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 copies of itself into the affected system:

• %User Temp%\svchost.exe
• %User Temp%\sys{random}.tmp

(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.)

It drops the following component file(s):

• %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.)

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"

It drops the following file(s) in the Windows Startup folder to enable its automatic execution at every system startup:

• %User Startup%\x.vbs -> includes execution code for malware's dropped copy in %User Temp%

(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.)

Other System Modifications

This Trojan modifies the following file(s):

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

It 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}

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Other Details

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

• http://{BLOCKED}.{BLOCKED}.183.40
• http://{BLOCKED}.{BLOCKED}.236.11
• http://{BLOCKED}.{BLOCKED}.202.170
• http://{pseudo-random domain}.{xyz/org/su/pw/ru}

It encrypts files with the following extensions:

• .3dm
• .3ds
• .3g2
• .3gp
• .7z
• .aes
• .apk
• .ARC
• .asc
• .asf
• .asm
• .asp
• .asset
• .avi
• .bak
• .bat
• .bik
• .bmp
• .brd
• .bsa
• .bz2
• .c
• .cgm
• .class
• .cmd
• .cpp
• .crt
• .cs
• .csr
• .CSV
• .d3dbsp
• .das
• .dat
• .db
• .dbf
• .dch
• .dif
• .dip
• .djv
• .djvu
• .DOC
• .docb
• .docm
• .docx
• .DOT
• .dotm
• .dotx
• .fla
• .flv
• .forge
• .frm
• .gif
• .gpg
• .gz
• .h
• .hwp
• .ibd
• .iwi
• .jar
• .java
• .jpeg
• .jpg
• .js
• .keywallet
• .lay
• .lay6
• .lbf
• .ldf
• .litemod
• .litesql
• .ltx
• .m3u
• .m4a
• .m4u
• .max
• .mdb
• .mdf
• .mid
• .mkv
• .mml
• .mov
• .mp3
• .mp4
• .mpeg
• .mpg
• .ms11
• .ms11 (Security copy)
• .MYD
• .MYI
• .n64
• .NEF
• .odb
• .odg
• .odp
• .ods
• .odt
• .onetoc2
• .otg
• .otp
• .ots
• .ott
• .p12
• .PAQ
• .pas
• .pdf
• .pem
• .php
• .pl
• .png
• .pot
• .potm
• .potx
• .ppam
• .pps
• .ppsm
• .ppsx
• .PPT
• .pptm
• .pptx
• .psd
• .pst
• .qcow2
• .rar
• .raw
• .rb
• .re4
• .RTF
• .sav
• .sch
• .sh
• .sldm
• .sldx
• .slk
• .sql
• .SQLITE3
• .SQLITEDB
• .stc
• .std
• .sti
• .stw
• .svg
• .swf
• .sxc
• .sxd
• .sxi
• .sxm
• .sxw
• .tar
• .tar
• .tbk
• .tgz
• .tif
• .tiff
• .txt
• .uop
• .uot
• .upk
• .vb
• .vbs
• .vdi
• .vmdk
• .vmx
• .vob
• .wallet
• .wav
• .wb2
• .wk1
• .wks
• .wma
• .wmv
• .xlc
• .xlm
• .XLS
• .xlsb
• .xlsm
• .xlsx
• .xlt
• .xltm
• .xltx
• .xlw
• .xml
• .zip

It does the following:

• It executes the following command to delete shadow copies:
  • vssadmin.exe Delete Shadows /All /Quiet

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 prevents encrypting files containing any of the strings in its full path name:

• winnt
• Application Data
• AppData
• Program Files (x86)
• Program Files
• thumbs.db
• $Recycle.Bin
• System Volume Information
• Windows