On Monday 21 April 2025 at 05:46 UTC, a memcached amplification targeted a tax authority portal customer in Western Europe. The attack peaked at 351.6 Gbps and lasted 42 minutes. Traffic originated from 4197 autonomous systems in 60 countries, predominantly compromised cloud VMs.
| Vector | memcached amplification |
| Peak | 351.6 Gbps |
| Duration | 42 min |
| Time to mitigation | 0.766 s |
| Attack traffic reaching origin | 0.065% |
| Legitimate traffic challenged | 0.66% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 26 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Keep origin IPs out of public DNS history.
- Review allow-listed partner ranges quarterly.