[Snort-sigs] PCRE and normalized content
spooker at ...2420...
Wed Jan 13 21:30:19 EST 2010
If you are using snort manual 22.214.171.124 it's there but in a "wrong
place" (page 131 with byte_test) . If you read the snort_manual from
snort 2.8.6 beta its in a "correct page"
Did you see that other thread anyway ?
Hope it helps.
On Thu, Jan 14, 2010 at 12:23 AM, Paul Schmehl <pschmehl_lists at ...3425...> wrote:
> Apparently I need to read your snort manual. The one I was looking at
> didn't have all those options. :-(
> Sure, I won't match 1>2, but I'll still match all equalities, which is
> important to me. I'm already catching a bunch of stuff we were missing
> --On January 13, 2010 6:08:52 PM -0600 "Rodrigo Montoro(Sp0oKeR)"
> <spooker at ...2420...> wrote:
>> I think you should read snort manual =)
>> Table 3.8: Snort specific modifiers for pcre
>> R Match relative to the end of the last pattern match. (Similar to
>> U Match the decoded URI buffers (Similar to uricontent and http uri)
>> P Match normalized HTTP request body (Similar to http client body)
>> H Match normalized HTTP request header (Similar to http header)
>> M Match normalized HTTP request method (Similar to http method)
>> C Match normalized HTTP request cookie (Similar to http cookie)
>> B Do not use the decoded buffers (Similar to rawbytes)
>> O Override the configured pcre match limit for this expression (See
>> section 2.1.3)
>> Anyway this rules will fail with a simples and 1<2 .
>> I tried once to write a rules but there are to many ways to write the
>> same query take a look at this thread
>> Anyway I don't thing this list is about writing new rules =)
>> On Wed, Jan 13, 2010 at 9:52 PM, Paul Schmehl <pschmehl_lists at ...3425...>
>>> This string: %20%61%6E%64%20%31%3D%31
>>> equals this string: ' and 1=1'
>>> after normalization. You can pick this up in a rule by using
>>> uricontent instead of content. But what do you do about PCRE? Is
>>> there a way to get PCRE to match against normalized content? Or will
>>> it only match against non-normalized content?
>>> I'm working on sql injection rules and using the following pcre:
>>> It works fine on 1=1 or 54=54, but fails on %31%3D%31, apparently
>>> because it's attempting to match against the non-normalized content.
>>> Paul Schmehl, Senior Infosec Analyst
>>> As if it wasn't already obvious, my opinions
>>> are my own and not those of my employer.
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>> Rodrigo Montoro (Sp0oKeR)
> Paul Schmehl, If it isn't already
> obvious, my opinions are my own
> and not those of my employer.
> WARNING: Check the headers before replying
Rodrigo Montoro (Sp0oKeR)
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