On Monday 27 January 2025 at 16:58 UTC, a SYN flood targeted a electronics retail customer in the Benelux. The attack peaked at 34.0 Gbps and lasted 52 minutes. Traffic originated from 3329 autonomous systems in 117 countries, predominantly mobile carrier ranges.
| Vector | SYN flood |
| Peak | 34.0 Gbps |
| Duration | 52 min |
| Time to mitigation | 0.779 s |
| Attack traffic reaching origin | 0.045% |
| Legitimate traffic challenged | 0.64% |
Timeline
The attack was preceded by a competitor’s product launch. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 33 points of presence.
What the customer saw
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
Nice to read a vendor blog that admits what went wrong.
The point about origin IPs leaking through certificate transparency logs is underrated.