On Friday 17 May 2024 at 12:25 UTC, a CLDAP reflection targeted a healthcare portal customer in Central Europe. The attack peaked at 381.8 Gbps and lasted 146 minutes. Traffic originated from 998 autonomous systems in 108 countries, predominantly compromised cloud VMs.
| Vector | CLDAP reflection |
| Peak | 381.8 Gbps |
| Duration | 146 min |
| Time to mitigation | 0.568 s |
| Attack traffic reaching origin | 0.010% |
| Legitimate traffic challenged | 0.43% |
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 30 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
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.
- Review allow-listed partner ranges quarterly.
Clear and practical, thanks.
Verified good bots and allow-listed partners bypass challenges entirely.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
Good question. We will cover that in a follow-up post.
The billing model is what got our finance team on board, honestly.
Verified good bots and allow-listed partners bypass challenges entirely.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Thanks — sharing this with our on-call team.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
The billing model is what got our finance team on board, honestly.
Verified good bots and allow-listed partners bypass challenges entirely.