On Monday 6 September 2021 at 22:50 UTC, a CLDAP reflection targeted a airline booking customer in North America. The attack peaked at 311.3 Gbps and lasted 17 minutes. Traffic originated from 1534 autonomous systems in 33 countries, predominantly misconfigured open reflectors.
| Vector | CLDAP reflection |
| Peak | 311.3 Gbps |
| Duration | 17 min |
| Time to mitigation | 0.889 s |
| Attack traffic reaching origin | 0.058% |
| Legitimate traffic challenged | 0.43% |
Timeline
The attack was preceded by a breaking political story. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 12 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.
- Enable authenticated origin pulls.