On Tuesday 1 July 2025 at 16:42 UTC, a memcached amplification targeted a tax authority portal customer in North America. The attack peaked at 55.0 Gbps and lasted 49 minutes. Traffic originated from 3932 autonomous systems in 97 countries, predominantly mobile carrier ranges.
| Vector | memcached amplification |
| Peak | 55.0 Gbps |
| Duration | 49 min |
| Time to mitigation | 0.896 s |
| Attack traffic reaching origin | 0.019% |
| Legitimate traffic challenged | 0.12% |
Timeline
The attack was preceded by a competitor’s product launch. 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
A brief increase in p99 latency of 102 ms during the first minute, then normal service.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.
Interesting that most attacks are under ten minutes. Our experience is similar.