[cod] CoD2 UDP flood
Marco Padovan
evcz at evcz.tk
Thu Feb 23 07:33:19 EST 2012
Ehm,
nope :D
You need all the lines John posted:
http://icculus.org/pipermail/cod/2012-January/015861.html
To make it works in centos5 / 6 change into that ruleset:
iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode srcip
--hashlimit-name getstatus --hashlimit-above 2/second -j QUERY-BLOCK
in this way (two different lines):
iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode srcip
--hashlimit-name getstatus --hashlimit 2/s -j RETURN
iptables -A QUERY-CHECK -j QUERY-BLOCK
all the other rules should be kept as they are :)
Il 23/02/2012 13:10, escapedturkey ha scritto:
> Thank you. I missed those lines.
>
> Here is what I have so far:
>
> /sbin/iptables -N QUERY-BLOCK
> /sbin/iptables -A QUERY-BLOCK -m recent --set --name blocked-hosts -j DROP
> /sbin/iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode srcip
> --hashlimit-name getstatus --hashlimit 2/s -j RETURN
> /sbin/iptables -A QUERY-CHECK -j QUERY-BLOCK
>
> Is this correct?
>
> Thank you again. =)
>
> On Thu, Feb 23, 2012 at 5:32 AM, Marco Padovan <evcz at evcz.tk
> <mailto:evcz at evcz.tk>> wrote:
>
> did you issued all the other commands?
>
> like:
>
> iptables -N QUERY-BLOCK
> iptables -A QUERY-BLOCK -m recent --set --name blocked-hosts -j DROP
>
> ?
>
> Il 23/02/2012 03:54, escapedturkey ha scritto:
>> iptables v1.4.7: Couldn't load target
>> `QUERY-BLOCK':/lib64/xtables/libipt_QUERY-BLOCK.so: cannot open
>> shared object file: No such file or directory
>>
>> Any ideas?
>>
>>
>> On Wed, Feb 22, 2012 at 4:51 PM, Marco Padovan <evcz at evcz.tk
>> <mailto:evcz at evcz.tk>> wrote:
>>
>> on centos5 and centos6
>>
>> modifying this line:
>> iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode srcip
>> --hashlimit-name getstatus --hashlimit-above 2/second -j
>> QUERY-BLOCK
>>
>> in this way (two different lines):
>> iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode srcip
>> --hashlimit-name getstatus --hashlimit 2/s -j RETURN
>> iptables -A QUERY-CHECK -j QUERY-BLOCK
>>
>> should mimic the same behaviour
>>
>> Il 22/02/2012 18:43, Geoff Goas ha scritto:
>>> Hi,
>>>
>>> On CentOS 5.5, /--hashlimit-above/ is not a valid option for
>>> the "hashlimit" match. Which version of iptables introduces
>>> this, and how can I mimic that same ruleset with the options
>>> available to me in version 1.3.5 of iptables?
>>>
>>> Thanks,
>>>
>>> On Fri, Jan 20, 2012 at 7:51 PM, John
>>> <lists.cod at nuclearfallout.net
>>> <mailto:lists.cod at nuclearfallout.net>> wrote:
>>>
>>> On 1/20/2012 3:27 PM, Marco Padovan wrote:
>>>> I was referring to dynamic filtering using -m recent
>>>>
>>>> [not] to manually adding IPs O.o
>>>
>>> Marco's right about this. The most effective way to
>>> prevent effects from these attacks on Linux is to use a
>>> combination of the "string", "hashlimit", and "recent"
>>> modules. Done right, the solution is mostly automatic,
>>> so you shouldn't need to manually add IPs.
>>>
>>> These commands, for instance, would block external IPs
>>> that send queries at a rate of 2/second or higher:
>>>
>>> # add a host to the banlist and then drop the packet.
>>> iptables -N QUERY-BLOCK
>>> iptables -A QUERY-BLOCK -m recent --set --name
>>> blocked-hosts -j DROP
>>>
>>> # is this a query packet? if so, block commonly attacked
>>> ports outright,
>>> # then see if it's a known attacking IP, then see if it
>>> is sending at a high
>>> # rate and should be added to the list of known
>>> attacking IPs.
>>> iptables -N QUERY-CHECK
>>> iptables -A QUERY-CHECK -p udp -m string ! --string
>>> "getstatus" --algo bm --from 32 --to 41 -j RETURN
>>> iptables -A QUERY-CHECK -p udp --sport 0:1025 -j DROP
>>> iptables -A QUERY-CHECK -p udp --sport 3074 -j DROP
>>> iptables -A QUERY-CHECK -p udp --sport 7777 -j DROP
>>> iptables -A QUERY-CHECK -p udp --sport 27015:27100 -j DROP
>>> iptables -A QUERY-CHECK -p udp --sport 25200 -j DROP
>>> iptables -A QUERY-CHECK -p udp --sport 25565 -j DROP
>>> # is it already blocked? continue blocking it and update
>>> the counter so it
>>> # gets blocked for at least another 30 seconds.
>>> iptables -A QUERY-CHECK -m recent --update --name
>>> blocked-hosts --seconds 30 --hitcount 1 -j DROP
>>> # check to see if it exceeds our rate threshold,
>>> # and add it to the list if it does.
>>> iptables -A QUERY-CHECK -m hashlimit --hashlimit-mode
>>> srcip --hashlimit-name getstatus --hashlimit-above
>>> 2/second -j QUERY-BLOCK
>>>
>>> # look at all the packets going to q3/cod*/et/etc servers
>>> iptables -A INPUT -p udp --dport 27960:29000 -j QUERY-CHECK
>>>
>>> The "recent" module makes it possible to block up to 100
>>> IPs at once with this method (any attackers beyond this
>>> would only be rate-limited). That number can be raised
>>> when the module is loaded, but I haven't seen 100
>>> attacks happening at once yet (typically it's maybe 5-20
>>> at once). You can see blocked hosts later by looking at
>>> /proc/net/xt_recent/blocked-hosts.
>>>
>>> (If you don't have "recent", you could get away without
>>> it -- just be aware that some of the packets will get
>>> through, increasing load on the game server. Without
>>> "hashlimit", you'd still see an advantage from the port
>>> checks, but you'd need to manually block IPs that are
>>> being hit on other ports. Without "string", you'd
>>> similarly be down to just port checks, and need to take
>>> out the other rules.)
>>>
>>> -John
>>>
>>> _______________________________________________
>>> cod mailing list
>>> cod at icculus.org <mailto:cod at icculus.org>
>>> http://icculus.org/mailman/listinfo/cod
>>>
>>>
>>>
>>>
>>> --
>>> /*Geoff Goas
>>> Systems Engineer*/
>>>
>>>
>>>
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>>> cod at icculus.org <mailto:cod at icculus.org>
>>> http://icculus.org/mailman/listinfo/cod
>>
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