Re: [ntp:questions] Possible new attack?
Evandro Menezes aevan...@gmail.com wrote: I've noticed a couple of NTP clients with the unusual avgint of 16s with hundreds of accesses to my NTP server in the pool. I added a restriction, in addition to the recommended ones already in place, to cope with the suspicious clients bumping the discard average threshold to 32s. Eventually, KoD kicked them out, but they returned again and again, but each time with a different source UDP port. I'd think that were it the case of an improperly configured, though kosher, NTP client, it would not haunt the server again after a KoD. I suspect that it's the case of zombie systems running some sort of DoS bot. If so, is this the behavior of the recent DRDoS attack or a new attack on NTP? Never send KoD on traffic that you don't like! It serves no useful purpose. Most badly behaving clients will ignore it, the worst ones will react to it with a quick re-try. It only drives up your outging traffic. Just drop the offending traffic, that saves you the effort of replying and makes it go away quicker. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Possible new attack?
On Mon, Oct 06, 2014 at 06:49:58PM -0700, Evandro Menezes wrote: On Monday, October 6, 2014 6:50:09 PM UTC-5, William Unruh wrote: Not only that but they are probably running ntp 3 systems, which does not have KOD. The suspects are purportedly NTPV4: remote address port local address count m ver rstr avgint lstint wnpgmb1154w-a-b 123 192.168.a.b 18 3 45f8 6 0 a-b.dyn.suddenlink.net 42324 192.168.a.b 1590 3 45f8 14 6 Out of curiousity, do you have a pcap file or tcpdump output you could share? I've been trying to fix widely used open source (S)NTP implementations to not poll frequently and I'm wondering if this is a client I know. -- Miroslav Lichvar ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Possible new attack?
Harlan Stenn wrote: William Unruh writes: Not only that but they are probably running ntp 3 systems, which does not have KOD. It would be really nice to be able to identify what these are - if somebody finds out please tell me. The OP could do e.g.: ntpq -cmrulist and look at the mrulist v column to see if they are 3 or 4 ...? -- E-Mail Sent to this address blackl...@anitech-systems.com will be added to the BlackLists. ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
