Ransom.Win32.PURELOCKER.A

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops files as ransom note. It avoids encrypting files with the following file extensions.

Arrival Details

This Ransomware 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 Ransomware adds the following processes:

• wmic shadowstorage SET MaxSpace=337000000 → resizes the maximum amount of storage space that can be used for shadow copy storage

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\{random characters}

Dropping Routine

This Ransomware drops the following files:

• {Malware Path}\dbg.txt → contains list of files it was unable to encrypt

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

• bootmgr
• bootsect.bak
• dbg.txt
• iconcache.db
• ntldr
• ntuser.dat
• thumbs.db
• your_files.txt

It avoids encrypting files found in the following folders:

• $Recycle.Bin
• Boot
• Google
• Microsoft
• Mozilla
• MSOCache
• Packages
• Python27
• Recycler
• System Volume Information
• Thunderbird

It appends the following extension to the file name of the encrypted files:

• .CR1

It drops the following file(s) as ransom note:

• {Encrypted Directory}\YOUR_FILES.txt
  

It avoids encrypting files with the following file extensions:

• .qm
• .dll
• .exe
• .ini
• .sys
• .lib
• .msg
• .ocx
• .log
• .url
• .lnk
• .cmd
• .bat
• .etl
• .ico
• .cpl
• .wpl
• .com
• .inf
• .msi
• .mui
• .hxw
• .hxh
• .oca
• .dmp
• .tmp
• .chm
• .hlp
• .cr1
• .readme
• .manifest
• .search-ms
• .appref-ms
• .library-ms
• .searchconnector-ms
• .old