On Tuesday 4 May 2021 at 07:21 UTC, a UDP reflection (NTP) targeted a online payments customer in the Benelux. The attack peaked at 197.9 Gbps and lasted 65 minutes. Traffic originated from 1239 autonomous systems in 8 countries, predominantly mobile carrier ranges.
| Vector | UDP reflection (NTP) |
| Peak | 197.9 Gbps |
| Duration | 65 min |
| Time to mitigation | 0.244 s |
| Attack traffic reaching origin | 0.036% |
| Legitimate traffic challenged | 0.14% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 18 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
Nice to read a vendor blog that admits what went wrong.
Clear and practical, thanks.
Great write-up. We saw almost the same pattern on our login endpoint last month.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?