Snort mailing list archives
RE: Sobre las reglas snort
From: "Hutchinson, Andrew" <Andrew.Hutchinson () Vanderbilt edu>
Date: Fri, 5 Jul 2002 11:32:58 -0500
Okay, my Spanish is marginal at best, so I'm replying in English. The "A+" refers to the tcp flags on the packet in question. In the alert you provided, the "A+" means that the ACK flag MUST be set, and any other flags MAY be set. Thus, an ACK, SYN-ACK, FIN-ACK, or an XMAS packet with everything set would all match this rule. The ACK flag is a must, the other flags can go either way. If the rule were written with only "flags: A", then the rule would only match if ONLY the ACK flag were set (i.e. a SYN-ACK would not match). Here are some other examples: flags: SF # Matches ONLY SYN-FIN flags: SF+ # Would match SYN-FIN, SYN-FIN-ACK, XMAS, would NOT match FIN-ACK, SYN-ACK, SYN, ACK, RST flags: SF* # Would match SYN-FIN, SYN-FIN-ACK, XMAS, FIN-ACK, SYN, and SYN-ACK, would NOT match ACK, RST So, in essence the "+" is like a logical "AND" (with the side-effect that non-included flags can be set and still match), while the "*" is like a non-exclusive "OR". Hope that this helps, Andrew -----Original Message----- From: fon Al [mailto:Alfon () maestrosdelweb com] Sent: Friday, July 05, 2002 11:10 AM To: snort-users () lists sourceforge net Subject: [Snort-users] Sobre las reglas snort Hola, Soy nuevo en la lista queria hacer una pregunta. En la creación de reglas Snort, que significa 'flags: A+;' me refiero al significado del +A por ejemplo: alert tcp $EXTERNAL_NET any -> $HOME_NET 113 (msg:"SCAN ident version"; flags: A+; content: "VERSION|0A|"; depth: 16;reference:arachnids,303; classtype:attempted-recon; sid:616; rev:1;) Según el manual dice que: + ALL flag, match on all specified flags plus any others * ANY flags, match....... Pero es que no tengo ni idea de que significa y que tiene que ver con ACK. Muchas gracias. Ps. Ya tienes tu correo @maestrosdelweb.com Consiguelo en http://www.maestrosdelweb.com ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Bringing you mounds of caffeinated joy. http://thinkgeek.com/sf _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=ort-users ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Bringing you mounds of caffeinated joy. http://thinkgeek.com/sf _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- Sobre las reglas snort fon Al (Jul 05)
- <Possible follow-ups>
- RE: Sobre las reglas snort Hutchinson, Andrew (Jul 05)