On Tuesday 25 July 2023 at 14:08 UTC, a CLDAP reflection targeted a sports betting customer in the Nordics. The attack peaked at 214.7 Gbps and lasted 135 minutes. Traffic originated from 1140 autonomous systems in 72 countries, predominantly misconfigured open reflectors.
| Vector | CLDAP reflection |
| Peak | 214.7 Gbps |
| Duration | 135 min |
| Time to mitigation | 0.897 s |
| Attack traffic reaching origin | 0.026% |
| Legitimate traffic challenged | 0.19% |
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 33 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Do you publish the edge IP ranges in a machine-readable format?
Nice to read a vendor blog that admits what went wrong.
Thanks — sharing this with our on-call team.
Good question. We will cover that in a follow-up post.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Good question. We will cover that in a follow-up post.