On Saturday 7 January 2023 at 07:20 UTC, a CLDAP reflection targeted a municipal services customer in the Nordics. The attack peaked at 79.5 Gbps and lasted 9 minutes. Traffic originated from 1206 autonomous systems in 47 countries, predominantly hijacked home routers.
| Vector | CLDAP reflection |
| Peak | 79.5 Gbps |
| Duration | 9 min |
| Time to mitigation | 0.749 s |
| Attack traffic reaching origin | 0.058% |
| Legitimate traffic challenged | 0.77% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 27 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
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
Solid runbook advice. The DNS-at-2am point hit home.
Nice to read a vendor blog that admits what went wrong.
Any plans to support per-tenant limits keyed on a JWT claim?
Good question. We will cover that in a follow-up post.
Is the risk score exposed in the logs so we can build our own dashboards on it?