Snort mailing list archives
Re: Flags rule option
From: Matt Kettler <mkettler () evi-inc com>
Date: Thu, 26 Sep 2002 21:06:22 -0400
Unlike content, I don't think snort allows multiple flags sections in a rule. Offhand I think flags: AR! will do what you want, which appears to be detecting anything to a client port which is initiated by an outside server. This will match any reasonable syn packet, along with synfin, etc. but won't trigger on fin-ack, reset, synack, etc.
Also beware, any active-mode ftp transfers will trigger this rule (or your original one), since that causes an outside server to syn (connect to) a >1024 port on your machine.
At 05:21 PM 9/26/2002 -0700, Bill McCarty wrote:
Hi all, I have the following Snort rule:alert tcp any any -> XXX.XXX.XXX.XXX 1024:65535 (flags:S+; flags:A!; msg:"Local suspicious inbound"; )This rule matches the following datagram: 09/26/02-15:49:14.256645 YYY.YYY.YYY.YYY:80 -> XXX.XXX.XXX.XXX:24247 TCP TTL:237 TOS:0x0 ID:0 IpLen:20 DgmLen:40 DF *****R** Seq: 0x2ED4C858 Ack: 0x0 Win: 0x0 TcpLen: 20I think that both flags options must be matched in order for the rule as a whole to match. Yet, the matching datagram does not have the S flag set. What am I missing?Thanks! --------------------------------------------------- Bill McCarty ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. 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
------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. 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:
- Flags rule option Bill McCarty (Sep 26)
- Re: Flags rule option Matt Kettler (Sep 26)
- Re: Flags rule option Bill McCarty (Sep 26)
- Re: Flags rule option Martin Roesch (Sep 26)
- Re: Flags rule option Bill McCarty (Sep 26)
- Re: Flags rule option Matt Kettler (Sep 26)