Commands are just packaged into the regular game packets, you couldn't filter them out specifically with a firewall without it processing the whole packet.
String matching also wouldn't work as the data is bit (rather than byte) aligned. Sent from my iPhone On 15 Jun 2012, at 17:49, David Parker <[email protected]> wrote: > I should clarify... Using an iptables rule like that assumes that the status > request packets are always the same size, and they are a different size than > the normal game data packets. You can also do string matching within packets > using iptables (if you have the appropriate modules installed), but on a game > server, that would probably add so much processing overhead it's not even > worth it. > > - Dave > > On 06/15/2012 12:40 PM, David Parker wrote: >> I guess one way Valve could solve this would be to change the way "status" >> works on the client. They could have the server send server-state >> information to the clients at some interval, like once per second, or >> perhaps each time something changes (player joins or leaves, map changes, >> etc.) and then have the "status" command on the client just read its most >> recent data. That would prevent status requests from hitting the server at >> all. It adds some overhead compared to the real-time request/reply method, >> but it eliminates the need to process each status request that comes in. >> >> Or, if the incoming "status" packets are always the same size, you could >> also use iptables to rate-limit them (just replace N with the packet size in >> bytes): >> >> iptables -A INPUT -p udp -m length --length N -m limit --limit 3/s -j ACCEPT >> >> (Note: I didn't test this iptables rule, I just slapped it together as a >> demonstration) >> >> - Dave >> >> On 06/14/2012 03:06 PM, Alvaro Gutierrez Lorenzo wrote: >>> I don't think it's still a popular attack, since it is only useful when you >>> can't ban in an effective way the attacker (e. g. Free-to-Play scheme). I >>> dont think it's a widely known attack, on my case it was just a single >>> person who was attacking all our servers, as we verified comparing IPs. >>> >>> What I would suggest you to do is to have SMAC (Sourcemod anti-cheat) >>> command monitor plugin running, and from time to time (or everytime find >>> there are lag issues) check this plugin's logs (called cmd_[date].log, >>> under the Sourcemod's log directory) to see if someone is attacking you by >>> this means. It's easy to spot even without actually opening the log file, a >>> usual day log will not grow over 1MB while when you have been attacked the >>> log will easily reach 300Mb (I've seen >3Gb log files on my server because >>> of this). Inside it looks like thousands of lines stating >>> "[date]: Console<0><Console><Console> executes: status" during a single >>> second. >>> >>> If you ever spot this attack, then you could take this measure to stop it. >>> Meanwhile, I would not take much care, since it's easy and quick to solve >>> (thanks to the people on this mailing list, thank you all again ;) ). >>> >>> El 14/06/2012 20:46, doc escribió: >>>> Kind of a scary thread, I do a lot of terrible data collection on my own >>>> server/website using the "status" command and I'd hate to have to alias it >>>> to nothing to avoid problems like this. >>>> >>>> Is this something I assume is important enough to look into? >>>> >>>> On Wed, Jun 13, 2012 at 5:40 AM, Alvaro Gutierrez Lorenzo< >>>> [email protected]> wrote: >>>> >>>>> It worked perfectly! Simple attack, simple solution. >>>>> Never thought of this ways, now it seems so obvious XD >>>>> I made plugins and searched for the most strange ways of solving it, yet >>>>> it was "single-line" simple ^^ >>>>> >>>>> Well, it disables status, but that's a minimal sacrifice (SMAC provides a >>>>> secure alternative also, so there's no problem at all). >>>>> I will spread this through the servers I know: each and every one is >>>>> victim of this issue, that makes over a dozen grateful servers& >>>>> communities, many thanks ^^ >>>>> >>>>> I've checked this happens without any mods, so some official attention on >>>>> this would be the perfect happy ending, but this workaround solves the >>>>> problem so everything fine! >>>>> >>>>> El 13/06/2012 4:04, 1nsane escribió: >>>>> >>>>> While not a good solution at all. Have you tried aliasing status to >>>>>> nothing? >>>>>> >>>>>> "alias status" >>>>>> >>>>>> This will obviously disable the status command entirely. But perhaps it >>>>>> won't kill the server then? >>>>>> >>>>>> On Tue, Jun 12, 2012 at 7:49 PM, Alvaro Gutierrez Lorenzo< >>>>>> [email protected]> wrote: >>>>>> >>>>>> Sorry for the "double mail", I just though that if the fix for that >>>>>>> removed the cooldown time for status, there would be no protection over >>>>>>> this command, making possible this attack. >>>>>>> Invalid Protocol mentionned this protection on an earlier mail. >>>>>>> >>>>>>> Is it a silly idea? I've never experienced such cooldown protection, >>>>>>> that >>>>>>> would explain why. >>>>>>> >>>>>>> >>>>>>> El 13/06/2012 1:31, Joe Brown escribió: >>>>>>> >>>>>>> This was used (and may still be) in hacks as a way to stop admins from >>>>>>>> using the status command to see your STEAMID in the client console. >>>>>>>> Spamming it like that blocked all clients connected to the server from >>>>>>>> being able to use the status command, preventing or extending the time >>>>>>>> it >>>>>>>> takes to ban someone. >>>>>>>> >>>>>>>> Correct me if I'm wrong but I thought the was fixed in an update. >>>>>>>> >>>>>>>> Date: Wed, 13 Jun 2012 01:23:23 +0200 >>>>>>>> >>>>>>>>> From: [email protected] >>>>>>>>> To: [email protected].****com<hlds_linux@list.** >>>>>>>>> valvesoftware.com<[email protected]>> >>>>>>>>> Subject: Re: [hlds_linux] Overflow attack to Source servers >>>>>>>>> >>>>>>>>> That's a critical detail I forgot to mention, so sorry: RCON is port >>>>>>>>> closed, so every attempt to access RCON gives a "Time Out". >>>>>>>>> >>>>>>>>> I'm totally sure it's "status", here I paste an excerpt from the SMAC >>>>>>>>> log, made just by the same plugin you suggest: >>>>>>>>> >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> Sat Mar 31 14:56:34 2012: Console<0><Console><Console> executes: >>>>>>>>> status >>>>>>>>> ... >>>>>>>>> >>>>>>>>> (Well an this goes on for thousands and thousands of lines, making >>>>>>>>> pretty ~1GB files each day XD) >>>>>>>>> >>>>>>>>> I added status as a SMAC blocked command, still no luck. (used >>>>>>>>> smac_addcmd as stated in the link you provided, but as you say SMAC >>>>>>>>> wont >>>>>>>>> block commands coming from the server). >>>>>>>>> >>>>>>>>> The command can be captured and processed prom a plugin, but in every >>>>>>>>> teast I made I always got client 0 (console) as the triggerer, (of >>>>>>>>> course testing from the game, through a clean client account, not from >>>>>>>>> console). I think the server has never blocked me from executing >>>>>>>>> status, >>>>>>>>> even reproducing the attack (which is just spamming status from a >>>>>>>>> game's >>>>>>>>> client console). >>>>>>>>> >>>>>>>>> The server would block it surely if it was marked as client triggered. >>>>>>>>> At least where I can personally try (TF2 dedicated, Linux), it's >>>>>>>>> always >>>>>>>>> executed as from console. Some other server owners are working with me >>>>>>>>> on this, and this works like this on their's too (CSS and CSGO >>>>>>>>> confirmed >>>>>>>>> to be vulnerable to this attack too). >>>>>>>>> >>>>>>>>> Something that comes to my mind is if some "lower" addon like Metamod >>>>>>>>> is actually always deflecting this command through the console; I need >>>>>>>>> to try again on a clean install to check it. >>>>>>>>> >>>>>>>>> ______________________________****_________________ >>>>>>>> To unsubscribe, edit your list preferences, or view the list archives, >>>>>>>> please visit: >>>>>>>> https://list.valvesoftware.****com/cgi-bin/mailman/listinfo/*** >>>>>>>> *hlds_linux<https://list.**valvesoftware.com/cgi-bin/** >>>>>>>> mailman/listinfo/hlds_linux<https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux> >>>>>>>> >>>>>>> ______________________________****_________________ >>>>>>> To unsubscribe, edit your list preferences, or view the list archives, >>>>>>> please visit: >>>>>>> https://list.valvesoftware.****com/cgi-bin/mailman/listinfo/*** >>>>>>> *hlds_linux<https://list.**valvesoftware.com/cgi-bin/** >>>>>>> mailman/listinfo/hlds_linux<https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux> >>>>>>> ______________________________**_________________ >>>>>> To unsubscribe, edit your list preferences, or view the list archives, >>>>>> please visit: >>>>>> https://list.valvesoftware.**com/cgi-bin/mailman/listinfo/**hlds_linux<https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux> >>>>>> >>>>> >>>>> ______________________________**_________________ >>>>> To unsubscribe, edit your list preferences, or view the list archives, >>>>> please visit: >>>>> https://list.valvesoftware.**com/cgi-bin/mailman/listinfo/**hlds_linux<https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux> >>>>> >>>> _______________________________________________ >>>> To unsubscribe, edit your list preferences, or view the list archives, >>>> please visit: >>>> https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux >>> >>> >>> _______________________________________________ >>> To unsubscribe, edit your list preferences, or view the list archives, >>> please visit: >>> https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux >> > > -- > > Dave Parker > Systems Administrator > Utica College > Integrated Information Technology Services > (315) 792-3229 > Registered Linux User #408177 > > > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list archives, please > visit: > https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds_linux
