nanog mailing list archives
Re: Reflection DDoS last week
From: Denys Fedoryshchenko <nuclearcat () nuclearcat com>
Date: Sat, 24 Aug 2019 22:01:34 +0300
Hi,Same happened in Lebanon(country). Similar pattern: carpet bombing for multiple prefixes of specific ASN. I suspect it is a new trend in DDoS-for-hire, and ISP who did not install data scrubbing appliances will feel severe pain from such attacks, since they use SYN + ACK from legit servers.
On 2019-08-21 22:44, Töma Gavrichenkov wrote:
Peace, Here's to confirm that the pattern reported before in NANOG was indeed a reflection DDoS attack. On Sunday, it also hit our customer, here's the report: https://www.prnewswire.com/news-releases/root-cause-analysis-and-incident-report-on-the-august-ddos-attack-300905405.html tl;dr: basically that was a rather massive reflected SYN/ACK carpet bombing against several datacenter prefixes (no particular target was identified). -- Töma On Sat, Aug 17, 2019, 1:06 AM Jim Shankland <nanog () shankland org> wrote:Greetings, I'm seeing slow-motion (a few per second, per IP/port pair) syn flood attacks ostensibly originating from 3 NL-based IP blocks: 88.208.0.0/18 [1] , 5.11.80.0/21 [2], and 78.140.128.0/18 [3] ("ostensibly" because ... syn flood, and BCP 38 not yet fully adopted). Why is this syn flood different from all other syn floods? Well ... 1. Rate seems too slow to do any actual damage (is anybody really bothered by a few bad SYN packets per second per service, at this point?); but 2. IPs/port combinations with actual open services are being targeted (I'm seeing ports 22, 443, and 53, just at a glance, to specific IPs with those services running), implying somebody checked for open services first; 3. I'm seeing this in at least 2 locations, to addresses in different, completely unrelated ASes, implying it may be pretty widespread. Is anybody else seeing the same thing? Any thoughts on what's going on? Or should I just be ignoring this and getting on with the weekend? JimLinks: ------ [1] http://88.208.0.0/18 [2] http://5.11.80.0/21 [3] http://78.140.128.0/18
Current thread:
- Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Töma Gavrichenkov (Aug 21)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Damian Menscher via NANOG (Aug 21)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Töma Gavrichenkov (Aug 21)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Damian Menscher via NANOG (Aug 27)
- Re: Reflection DDoS last week Denys Fedoryshchenko (Aug 28)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Töma Gavrichenkov (Aug 21)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Damian Menscher via NANOG (Aug 21)
- Re: Reflection DDoS last week (was: syn flood attacks from NL-based netblocks) Amir Herzberg (Aug 21)
- Re: Reflection DDoS last week Denys Fedoryshchenko (Aug 24)