On Monday 10 November 2025 at 07:44 UTC, a SYN flood targeted a crypto exchange customer in Central Europe. The attack peaked at 307.9 Gbps and lasted 137 minutes. Traffic originated from 1105 autonomous systems in 76 countries, predominantly compromised cloud VMs.
| Vector | SYN flood |
| Peak | 307.9 Gbps |
| Duration | 137 min |
| Time to mitigation | 0.891 s |
| Attack traffic reaching origin | 0.062% |
| Legitimate traffic challenged | 0.66% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 17 points of presence.
What the customer saw
A brief increase in p99 latency of 49 ms during the first minute, then normal service.
Recommendations
- Enable authenticated origin pulls.
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.