[Snort-users] Check for NO TCP Flags set?

Matt Kettler mkettler at ...4108...
Fri May 9 13:11:05 EDT 2003


At 02:39 PM 5/9/2003 -0400, Sheahan, Paul wrote:
>I know I can check for flags set using Flags:S for example. Though I was
>curious if there is a way to check for NO flags being set?. I read that this
>may be seen in illicit servers.

Actually, flags:S checks for Syn bit set and all the other bits cleared. 
Flags: S+ is just a single bit check..

If you RTFM:
http://www.snort.org/docs/writing_rules/chap2.html#tth_sEc2.3.13

Flags:0 specifies no bits set.





More information about the Snort-users mailing list