Good analyze Hugo,
I believe that all of this volumetric attack is just noise to hide the real attack that really killed your webserver. TCP Flag: SYN: 100% I would start with this line and I agree that Roland’s deck might have something about SYN flood. Jean From: Hugo Slabbert <[email protected]> Sent: February 8, 2021 2:19 PM To: Compton, Rich A <[email protected]> Cc: Mike Hammett <[email protected]>; Jean St-Laurent <[email protected]>; NANOG list <[email protected]> Subject: Re: [EXTERNAL] Re: Retalitory DDoS Was gonna come to add that. That and maybe some UDP frags. You may want to have your hosting provider block all inbound traffic from reaching your server IP except TCP port 443 (or 80 or whatever port you actually use) somewhere upstream. Can also consider dropping by UDP source port on that 3072 and other common reflection vectors if you've got UDP-based destinations to deal with. The SYN floods are a different beast; though probably not volumetric, needs enough capacity (TCP reverse proxies / LBs / etc) to handle that and possibly things like SYN cookies. I'll let folks more versed than myself answer there, though. Roland probably has a deck ready to link ;) -- Hugo Slabbert | email, xmpp/jabber: [email protected] <mailto:[email protected]> pgp key: B178313E | also on Signal On Mon, Feb 8, 2021 at 10:10 AM Compton, Rich A <[email protected] <mailto:[email protected]> > wrote: FYI, that looks like a Web Services Dynamic Discovery UDP amplification DDoS attack. https://blogs.akamai.com/sitr/2019/09/new-ddos-vector-observed-in-the-wild-wsd-attacks-hitting-35gbps.html Very easily executed by a booter service. You may want to have your hosting provider block all inbound traffic from reaching your server IP except TCP port 443 (or 80 or whatever port you actually use) somewhere upstream. This can help reduce the impact of DDoS attacks on your server. -Rich From: NANOG <[email protected] <mailto:[email protected]> > on behalf of Mike Hammett <[email protected] <mailto:[email protected]> > Date: Monday, February 8, 2021 at 10:58 AM To: Jean St-Laurent <[email protected] <mailto:[email protected]> > Cc: NANOG list <[email protected] <mailto:[email protected]> > Subject: [EXTERNAL] Re: Retalitory DDoS CAUTION: The e-mail below is from an external source. Please exercise caution before opening attachments, clicking links, or following guidance. I don't have RTBH, no. It's just a web server. Now how my hosting provider handled it, I'm not sure. I don't know if they just dropped me internally, or if they used RTBH with their upstreams and peers. Only being 2.5 gigs, that should be well within their ability to handle internally, but I guess why would you if you didn't have to? ----- Mike Hammett <http://www.ics-il.com/> Intelligent Computing Solutions <https://www.facebook.com/ICSIL> Midwest Internet Exchange The Brothers WISP _____ From: "Jean St-Laurent" <[email protected]> To: "Mike Hammett" <[email protected]> Cc: "NANOG list" <[email protected]> Sent: Monday, February 8, 2021 11:53:43 AM Subject: RE: Retalitory DDoS You got RTBH? From: Mike Hammett <[email protected]> Sent: February 8, 2021 12:50 PM To: Jean St-Laurent <[email protected]> Cc: NANOG list <[email protected]> Subject: Re: Retalitory DDoS In my case, it was against a server not on my own network, so my impact was a blackhole for an hour at 4 AM local time. I likely wouldn't have even noticed it, had I not received the threat email, nor the ticket my web host's NOC opened. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP _____ From: "Jean St-Laurent" <[email protected]> To: "Mike Hammett" <[email protected]>, "NANOG list" <[email protected]> Sent: Monday, February 8, 2021 11:42:12 AM Subject: RE: Retalitory DDoS Nice report, If you would have to pick up just one vector out of this “multi-vector” attack, which one seems to be the one that had the bigger effect on your network or service? Was it degraded or total service interruption? Jean From: NANOG <[email protected]> On Behalf Of Mike Hammett Sent: February 8, 2021 8:43 AM To: NANOG list <[email protected]> Subject: Re: Retalitory DDoS Mike, I've attached the full information we got from our DDOS protection system below. We had a large number of ping loss and data loss tickets begin opening up for devices sharing the cabinet chi18-313. The high traffic and interference was determined to be caused by incoming traffic to the ip address [Not hard to find, but redacted anyway]. Our network engineers will be back in after 9am until 5pm CST. They have greater access to the network and may be able to give you more details. Location : Chicago Event Time : 2021-02-08 04:17:38 CST (-0600) Destination IP: [Not hard to find, but redacted anyway] Traffic : 2520 Mbps 382880 pps Fragmentation : 11% Top Transport Protocol: . 99% Protocol # 17 (UDP) TCP Flag: SYN: 100% ACK: 0% RST: 0% FIN: 0% Top Source Port: . 61% Port # 3702 . 38% Port # 0 Top Destination Port: . 38% Port # 0 . 14% Port # 45934 . 9% Port # 23680 . 8% Port # 35023 . 7% Port # 25966 Top Source IP: . 0% 112.164.127.17 Number of unique IP: 7110 Total Bytes : 1259961437 Total Packets : 1531559 Duration : 4s Report Run Time : 151.3ms The 30 day null route count is: 0 Number of hours to null route : 1 Location : Chicago Event Time : 2021-02-08 04:02:38 CST (-0600) Destination IP: [Not hard to find, but redacted anyway] Traffic : 1817 Mbps 275483 pps Fragmentation : 13% Top Transport Protocol: . 99% Protocol # 17 (UDP) TCP Flag: SYN: 99% ACK: 0% RST: 0% FIN: 0% Top Source Port: . 56% Port # 3702 . 43% Port # 0 Top Destination Port: . 43% Port # 0 . 19% Port # 25966 . 19% Port # 35023 . 17% Port # 23680 Top Source IP: . 0% 90.49.167.239 Number of unique IP: 3577 Total Bytes : 953894831 Total Packets : 1157017 Duration : 4.199s Report Run Time : 306.8ms The 30 day null route count is: 0 Number of hours to null route : 1 Liam Doring Systems Administrator ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP _____ From: "Mike Hammett" <[email protected]> To: "NANOG list" <[email protected]> Sent: Monday, February 8, 2021 5:46:26 AM Subject: Retalitory DDoS Is there a club for people that have been DDoSed? If so, count me in. This one was directed at me (as opposed to one of my customers) because I got an e-mail explaining why I was getting DDoSed. Is that aspect common? There were also some racial and sexual accusations that were made that clearly aren't true and just speak to the intelligence of people like this. Is it safe to assume that they completely anonymized the email they sent to me? Is there anyone I should be reporting this to? I thought my site was running in Cloudflare, but my individual server was still attacked, so I gotta figure out where I screwed that up. https://www.dropbox.com/s/rrrx90jvy09h26s/ICS%20DDoS.png?dl=0 ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP The contents of this e-mail message and any attachments are intended solely for the addressee(s) and may contain confidential and/or legally privileged information. 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