On Sep 19, 2006, at 7:25 PM, A User wrote:



Is there a way to enable "find_service" to use UDP results?

UDP services do not send out a banner, and most of them do not send anything back when they receive what they consider to be a "malformed packet" (I'm leaving aside services such as SNMP which won't reply to properly formed packets which do not contain the proper "secret" [the community string in the case of snmp]). So doing service recognition actually requires sending nearly as many probes as there are services which the find_udp_service plugin would recognize, and coming up with good probes would be a non-trivial task when dealing with obscure services.

To make things worse, a lot of UDP services are single-threaded/ processed and tend to be extremely fragile -- so sending a fairly large number of probes will either crash the service, stall it into an infinite loop, or just prevent it from replying to other legitimate requests.

So we do not do full service recognition for UDP ports -- this is not really doable, this is extremely slow and this will disrupt many, many things, for very little actual benefits (the biggest class of UDP services which could 'easily' be reconignized are MS/SUN RPC services -- and you can get their list provided that you can talk to the portmapper) -- we have probes for tons of them which run on fixed ports, though.


                                                -- Renaud
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