2011/4/8 J. Hellenthal <jh...@dataix.net> > On Thu, Apr 07, 2011 at 07:54:56PM +0200, Ermal Luçi wrote: > >On Thu, Apr 7, 2011 at 5:14 PM, Quentin Narvor <quentin.nar...@gmail.com> > wrote: > >> 2011/4/7 Ermal Luçi <e...@freebsd.org> > >> > >>> On Thu, Apr 7, 2011 at 10:21 AM, Quentin Narvor > >>> <quentin.nar...@gmail.com> wrote: > >>> > Hello, > >>> > > >>> > My name is Quentin Narvor and I am currently working on intrusion > >>> detection. > >>> > I use Freebsd 8.2 and I recently needed pf to be able to dynamically > fill > >>> in > >>> > tables according pass rule. > >>> > > >>> > For performances reasons, I didn't want to do it with a script and > pfctl. > >>> > Then, with the help of Mr Nicolas Greneche, I made this patch named > >>> "add". > >>> > It enables pf to add src ip or dst ip in a table when a match occurs > on a > >>> > pass rule. > >>> > > >>> > >>> I cannot see, apart collecting ips in tables, anything else that > >>> cannot be done through pf(4) tags! > >>> Can you please describe a use case for this patch? > >> > >> > >> Indeed, it enables pf to change its behaviour toward some hosts > dynamically. > >> I will build a blacklist of ip which have been recognized as compromized > >> (botnets, spam, etc). I build a table with thoses IP. > >> > >> If I match a connection between one host of my internal network and one > >> blacklisted ip, there are chances that this host is infected. > >> I want to do a comprehensive capture of this host connections by adding > src > >> ip to a table of hosts to watch. A dup-to rule dump traffic from "host > to > >> watch" table to a sensor. > >> > >> Here are the rules : > >> pass in on $int_if from any to <blacklist> add ipsrc <infected_hosts> > >> pass in on $int_if dup-to ($sensor_if, sensor_ip) from <infected_hosts> > to > >> any > > > >Hmm, the below should work. > > > >..... > >pass in on $int_if from any to <blacklist> tag SUSPECT > >pass in on $int_if dup-to ($sensor_if, sensor_ip) from all tagged SUSPECT > >..... > > This won't work in my case. It would work if I want to capture only connections from my host to a blacklisted one. But I want to capture all the traffic of my host (not only the one to any blacklisted host) after a connection of this host to a blacklisted one occurs.
Source connection tracking would probably also work here too but unless > you are planning on filling up RAM per table usage I would certainly > suggest using tagging. > > An example of what I use for src connection tracking that overloads to a > blacklist would be one for SSH logins. > > pass in log quick proto tcp from !<trusted> port >1023 to any port > $shports label "Login/SSH:$dstport" keep state (max-src-conn 5, > max-src-conn-rate 15/30 overload <blacklist> flush global) > > But this may not be exactly what your looking for even though it could > be tricked out to put every IP into a table but like I said your going > to be filling up some RAM fairly quickly by keeping those hosts in a > table depending on how often your rule is going to match. > > I have seen the option overload. I could have used it if it was possible to set max_src_conn to 0 : overload table would have been filled in as soon as a connection to a blacklisted host occurs. In my case, hosts which will be added to the table are the one on my internal network. Although this is a university, number of ip addresses which will be added in a table is limited, I don't worry about RAM usage. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
