Snort mailing list archives
Re: [Emerging-Sigs] Errors with the Snort manual
From: Mike Cox <mike.cox52 () gmail com>
Date: Thu, 18 Feb 2010 14:12:19 -0600
I fail to see how the PCRE "/ABC.{1}DEF/" maps to "content:"ABC"; content:"DEF"; distance:1;" The PCRE matches the string "ABC" followed by any single byte (note the superfluous "{1}" making the PCRE more confusing IMHO) followed by the string "DEF". As for the content matches, the first content match matches the string "ABC". So far so good. The second content match skips single byte and then starts looking to match the string "DEF". So the string "ABCDEF" would not match either, the string "ABCXDEF" would match both, and the string "ABCDXYZDEF" would match the content keywords but not the PCRE. This disparity in matching makes me question the "mapping" of the PCRE to the content matches. Yes, there are strings that will match both but it is clearly not a 1 to 1 mapping. -Mike Cox On Thu, Feb 18, 2010 at 1:58 PM, evilghost () packetmail net < evilghost () packetmail net> wrote:
You are absolutely correct, this has been resolved in the 2.8.5.1 manual. Evidently I did report it after all (couldn't remember) or it was resolved without my reporting. Thanks Joel. -evilghost Joel Esler wrote:Evilghost, I have to go off of the current version of the manual, as we put out corrections and additions to the manual with every version of Snort. I am looking at the 2.8.5.1 version that is currently on Snort.org, the REGEX in 3.5.6 reads: "/ABC.{1}DEF/" and the example is (content:"ABC"; content:"DEF"; distance:1;). This is correct. In 3.5.7 it says "This rule constrains the search of EFG to not go past 10 bytes past the ABC match." The example is (content:"ABC"; content:"EFG"; within:10;) -- which is correct. As for there being no "D". There is nothing mentioned about the letterD.J On Thu, Feb 18, 2010 at 2:37 PM, evilghost () packetmail net <mailto:evilghost () packetmail net> <evilghost () packetmail net <mailto:evilghost () packetmail net>> wrote: Hello, There was a discussion on ET about some errors in the Snort manual.Icannot remember if I reported these or not. The Snort 2.8.4 manual appears to be inaccurate or wrong in a few places, specifically: Page #114, section 3.5.6, the REGEX used to explain figure 3.16 is incorrect. Page #114, section 3.5.7, the "10 bytes past the ABCDE match"verbiageis incorrect, there is no "D" in figure 3.17 nor is the explanationoffigure 3.17 correct. I did not check 2.8.5 but I assume these may persist there as well. Thanks -evilghost _______________________________________________ Emerging-sigs mailing list Emerging-sigs () emergingthreats net <mailto:Emerging-sigs () emergingthreats net> http://lists.emergingthreats.net/mailman/listinfo/emerging-sigs Support Emerging Threats! Get your ET Stuff! Tshirts, Coffee Mugs and Lanyardshttp://www.emergingthreats.net/index.php/support-et-and-buy-et-schwag.html-- Joel Esler 302-223-5974_______________________________________________ Emerging-sigs mailing list Emerging-sigs () emergingthreats net http://lists.emergingthreats.net/mailman/listinfo/emerging-sigs Support Emerging Threats! Get your ET Stuff! Tshirts, Coffee Mugs and Lanyards http://www.emergingthreats.net/index.php/support-et-and-buy-et-schwag.html
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Current thread:
- Errors with the Snort manual evilghost () packetmail net (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual evilghost () packetmail net (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Mike Cox (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual evilghost () packetmail net (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual evilghost () packetmail net (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual evilghost () packetmail net (Feb 18)
- Re: [Emerging-Sigs] Errors with the Snort manual Joel Esler (Feb 18)