Ivan Ristic | 4 Sep 17:01
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Re: Has anyone ever used multiMatch?

I don't know, I haven't thought about it. I prefer not to take
shortcuts. That way, I don't have to consider undesired consequences.

On Fri, Sep 4, 2009 at 11:53 AM, Nick Gearls<nickgearls <at> gmail.com> wrote:
> What's the exact problem of using only
>   t:none,t:htmlEntityDecode,t:cssDecode,t:jsDecode
>
> Do you see a possibility of missing an attack, or getting a false positive?
>
> Nick
>
>
> Ivan Ristic wrote:
>> To respond to my own email, I've never used multiMatch. I did
>> encounter a situation where multiMatch would be useful, but it didn't
>> quite do what I needed. As an example, below is an extract from some
>> work that I never finished (it might have gone into the new Core
>> Rules, though).
>>
>> ------------------------
>> # Do not allow control characters apart from horizontal tab (9/0x09),
>> # line feed (10/0x0a) and carriage return (13/0x10).
>> #
>> # Ref: http://en.wikipedia.org/wiki/Control_character
>> # Ref: http://www.w3.org/MarkUp/html3/specialchars.html
>> #
>> SecRule ARGS "@validateByteRange 9,10,13,32-255" \
>>     t:none
>>
>> # Verify for invalid bytes in HTML content.
>> #
>> SecRule ARGS "@validateByteRange 9,10,13,32-255" \
>>     t:none,t:htmlEntityDecode
>>
>> # Verify for invalid bytes in JavaScript context.
>> #
>> SecRule ARGS "@validateByteRange 9,10,13,32-255" \
>>     t:none,t:htmlEntityDecode,t:jsDecode
>>
>> # Verify for invalid bytes in CSS context.
>> #
>> SecRule ARGS "@validateByteRange 9,10,13,32-255" \
>>     t:none,t:htmlEntityDecode,t:cssDecode
>>
>> # TODO The above could be combined into one, really.
>> ------------------------
>>
>> Three of the above rules could be combined into one using multiMatch,
>> but not all of them since there's a branch in the logic.
>>
>>
>>
>> On Fri, Aug 21, 2009 at 3:46 PM, Ivan Ristic<ivan.ristic <at> gmail.com> wrote:
>>> I am really curious, has anyone ever used (or even thought about
>>> using) the multiMatch action?
>>>
>>> http://www.modsecurity.org/documentation/modsecurity-apache/2.5.9/modsecurity2-apache-reference.html#N1182A
>>>
>>> --
>>> Ivan Ristic
>>> Security assessment of your SSL servers
>>> https://www.ssllabs.com/ssldb/
>>
>
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--

-- 
Ivan Ristic
Security assessment of your SSL servers
https://www.ssllabs.com/ssldb/

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Gmane