On Thursday 29 June 2023 at 23:53 UTC, a SYN flood targeted a online payments customer in North America. The attack peaked at 55.8 Gbps and lasted 64 minutes. Traffic originated from 1807 autonomous systems in 65 countries, predominantly a rented booter service.
| Vector | SYN flood |
| Peak | 55.8 Gbps |
| Duration | 64 min |
| Time to mitigation | 0.323 s |
| Attack traffic reaching origin | 0.030% |
| Legitimate traffic challenged | 0.76% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 29 points of presence.
What the customer saw
A brief increase in p99 latency of 116 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Nice to read a vendor blog that admits what went wrong.
How do you avoid challenging uptime monitors and partners?
Thanks! Yes — the risk score and its components are included in every log record.
Interesting that most attacks are under ten minutes. Our experience is similar.
Thanks — sharing this with our on-call team.