Snort mailing list archives
Re: Rules across tcp headers & http headers/payload
From: "lists () packetmail net" <lists () packetmail net>
Date: Mon, 4 Mar 2013 12:17:31 -0600
On 03/04/2013 04:50 AM, Andy Richards wrote:
1) a tcp syn sent to the client followed by... 2) a http POST from the client to certain URL for example "POST /someurl" followed by... 3) a http payload to the client for example beginning with "HTTP/1.1 200 OK..." followed by... 4) a tcp fin to the client
Your firewall shouldn't be passing traffic with invalid state, so I believe #1 to be unnecessary. You could probably do this with flowbits but I'm not certain it's going to scale verify well. Example, I'm uncertain of direction, so I'm going 'any any' alert tcp any any -> any any (msg:"NOALERT HTTP POST to /someurl"; flow:established,to_server; content:"POST"; http_method; content:"/someurl"; http_uri; flowbits:set,custom.http.req; flowbits:noalert; sid:x; rev:1;) alert tcp any any -> any any (msg:"NOALERT HTTP 200 Response from POST to /someurl"; flow:established,from_server; content:"200"; http_stat_code; flowbits:isset,custom.http.req; flowbits:set,custom.http.resp; flowbits:noalert; sid:x; rev:1;) alert tcp any any -> any any (msg:"HTTP Req to /someurl with HTTP 200 Resp and TCP FIN set"; flow:established,to_server; flags:F*; flowbits:isset,custom.http.resp; sid:x; rev:1;) I really don't understand the use case though and this is kind of a really horrible way to abuse the IDS. Seems like an intelligent firewall not passing invalid state traffic and W3C logs would produce more reliable information. ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Snort-sigs mailing list Snort-sigs () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-sigs http://www.snort.org Please visit http://blog.snort.org for the latest news about Snort!
Current thread:
- Rules across tcp headers & http headers/payload Andy Richards (Mar 04)
- Re: Rules across tcp headers & http headers/payload waldo kitty (Mar 04)
- Re: Rules across tcp headers & http headers/payload lists () packetmail net (Mar 04)
- Re: Rules across tcp headers & http headers/payload Andy Richards (Mar 05)
- Re: Rules across tcp headers & http headers/payload lists () packetmail net (Mar 05)
- Re: Rules across tcp headers & http headers/payload Andy Richards (Mar 05)