mod-security-users

RE: [mod-security-users] SelectiveFilter doesn't seem to work with //

[PERA, C. (S. TRANSICIEL) <chr...@ai...>]

Hello,

Thanks for your previous answer.

I have an other question,

Where can i find the list of characters that they need to put one "\" before, when i try to declare them in rules?
Example:
SecFilterSelective REQUEST_URI "/*" Deny
SecFilterSelective REQUEST_URI "./" Deny
SecFilterSelective REQUEST_URI "/." Deny
SecFilterSelective REQUEST_URI "<" Deny
etc.

I have seen in your documentation that i have to set "\./" instead of "./", but i don't find the information for the others.

Thanks a lot,

Christophe


-----Original Message-----
From: Ivan Ristic [mailto:iv...@we...]
Sent: 27 January 2006 18:59
To: PERA, Christophe
Cc: mod...@li...
Subject: Re: [mod-security-users] SelectiveFilter doesn't seem to work
with //




PERA, Christophe wrote:
> Hello,
>
> I try to implement the following rule but mod_sec doesn't match:
>
> SecFilterSelective REQUEST_URI "//" deny
>
> I don't understand because all other rules are well performed.
>
> Could you say me how to implement it?

  You can't, at least not yet. ModSecurity automatically compresses
  consecutive / characters into one - that's why yours does not
  match.

  FYI future releases are likely to allow you to configure
  exactly which normalisation methods to apply, and it will become
  possible to avoid the problem.

--

Ivan Ristic, Technical Director
Thinking Stone, http://www.thinkingstone.com
Tel: +44 20 8141 2161, Fax: +44 87 0762 3934



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Re: [mod-security-users] SelectiveFilter doesn't seem to work with //

[Ivan R. <iv...@we...>]

PERA, Christophe (SOGETI TRANSICIEL) wrote:
> Hello,
> 
> Thanks for your previous answer.
> 
> I have an other question,
> 
> Where can i find the list of characters that they need
> to put one "\" before, when i try to declare them in rules?

  Apache 2.x uses the PCRE regex library. Its documentation
  is located at:

  http://www.pcre.org/pcre.txt

  Here's what it says on metacharacters:

--------------------
       There are two different sets of metacharacters: those that  are  recog-
       nized  anywhere in the pattern except within square brackets, and those
       that are recognized in square brackets. Outside  square  brackets,  the
       metacharacters are as follows:

         \      general escape character with several uses
         ^      assert start of string (or line, in multiline mode)
         $      assert end of string (or line, in multiline mode)
         .      match any character except newline (by default)
         [      start character class definition
         |      start of alternative branch
         (      start subpattern
         )      end subpattern
         ?      extends the meaning of (
                also 0 or 1 quantifier
                also quantifier minimizer
         *      0 or more quantifier
         +      1 or more quantifier
                also "possessive quantifier"
         {      start min/max quantifier

       Part  of  a  pattern  that is in square brackets is called a "character
       class". In a character class the only metacharacters are:

         \      general escape character
         ^      negate the class, but only if the first character
         -      indicates character range
         [      POSIX character class (only if followed by POSIX
                  syntax)
         ]      terminates the character class

       The following sections describe the use of each of the  metacharacters.
--------------------

-- 
Ivan Ristic, Technical Director
Thinking Stone, http://www.thinkingstone.com
ModSecurity: Open source Web Application Firewall