On Thursday 27 May 2021 at 05:33 UTC, a SYN flood targeted a online payments customer in Southeast Asia. The attack peaked at 163.0 Gbps and lasted 7 minutes. Traffic originated from 1963 autonomous systems in 22 countries, predominantly mobile carrier ranges.
| Vector | SYN flood |
| Peak | 163.0 Gbps |
| Duration | 7 min |
| Time to mitigation | 0.458 s |
| Attack traffic reaching origin | 0.075% |
| Legitimate traffic challenged | 0.21% |
Timeline
The attack was preceded by a publicly announced sales event. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 22 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.