NAME
    Snort::Rule - Perl extension for dynamically building snort rules

SYNOPSIS
      use Snort::Rule;
      $rule = Snort::Rule->new(
            -action => 'alert',
            -proto  => 'tcp',
            -src    => 'any',
            -sport  => 'any',
            -dir    => '->',
            -dst    => '192.188.1.1',
            -dport  => '44444',
      );

      $rule->opts('msg','Test Rule"');
      $rule->opts('threshold','type limit,track by_src,count 1,seconds 3600');
      $rule->opts('sid','500000');

      print $rule->string()."\n";

      OR

      $rule = 'alert tcp $SMTP_SERVERS any -> $EXTERNAL_NET 25 (msg:"BLEEDING-EDGE POLICY SMTP US Top Secret PROPIN"; flow:to_server,established; content:"Subject|3A|"; pcre:"/(TOP\sSECRET|TS)//[\s\w,/-]*PROPIN[\s\w,/-]*(?=//(25)?X[1-9])/ism"; classtype:policy-violation; sid:2002448; rev:1;)';

      $rule = Snort::Rule->new(-parse => $rule);
      print $rule->string()."\n";

DESCRIPTION
    This is a very simple snort rule object. It was developed to allow for
    scripted dynamic rule creation. Ideally you could dynamically take a
    list of bad hosts and build an array of snort rule objects from that
    list. Then write that list using the string() method to a snort rules
    file.

OBJECT METHODS
  new
    Reads in the initial headers to generate a rule and constructs the
    snort::rule object around it.

    Accepts:

      -action => [string] ? [alert|log|pass|...] : 'alert'
      -proto => [string] ? [ip|udp|tcp|...] : 'IP'
      -src => [string] ? [$strIp] : 'any'
      -sport => [int] ? [$sport] : 'any'
      -dir => [string] ? [->|<-|<>] : '->'
      -dst => [string] ? [$strIp] : 'any'
      -dport => [int] ? [$dport] : 'any'
      -opts => [hashref] ? [hashref] : '';

      -parse => $strRule # for parsing an existing rule into the object

    Returns: OBJECTREF

  string
    Outputs the rule in string form.

      print $sr->string()."\n";

    Prints "options only" string:

      print $sr->string(-optionsOnly => 1)."\n";

  action
    Sets and returns the rule action [alert,log,pass,...]

      $rule->action('alert');

  proto
    Sets and returns the protocol used in the rule [tcp,icmp,udp]

      $rule->proto('tcp');

  src
    Sets and returns the source used in the rule. Make sure you use SINGLE
    QUOTES for variables!!!

      $rule->src('$EXTERNAL_NET');

  sport
    Sets and returns the source port used in the rule

      $rule->sport(80);

  dir
    Sets and returns the direction operator used in the rule, -> <- or <>

      $rule->dir('->');

  dst
    Sets and returns the destination used in the rule

      $rule->dst('$HOME_NET');
      $rule->dst('192.168.1.1');

  dport
    Sets and returns the destination port used in the rule

      $rule->dport(6667);

  opts
    Sets an option and a value used in the rule. This currently can only be
    done one set at a time, and is printed in the order it was set.

      $rule->opts(option,value);
      $rule->opts('msg','this is a test rule');

    This will return a hashref: $hashref->{$keyOrderValue}->{option} and
    $hashref->{$keyOrderValue}->{value}

      my $hashref = $rule->opts();

    There is a fixQuotes() function that reads through this information
    before setting it, just to ensure the right options are sane. It's a
    very very basic function, but it seems to get the job done.

    This method will also accept HASHREF's for easier use:

      $rule->opts({
            msg     => 'test1',
            rev     => '222',
            content => 'Subject|3A|',
            nocase => '',
      });

      By passing an option => '', the parser will set its value to "''". When $self->string() is called, the option will be written as: option;
      ex: nocase => '', will result in an option output of: ...., nocase; ...

  opt
    Gets the value of the first option with a given name.

      $rule->opt(option);
      print $rule->opt('sid') . ': ' . $rule->opt('msg');

COPYRIGHT AND LICENSE
    Copyright (C) 2006 by Wes Young

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself, either Perl version 5.8.6 or, at
    your option, any later version of Perl 5 you may have available.