On Thursday 29 May 2025 at 19:30 UTC, a memcached amplification targeted a retail banking customer in the Benelux. The attack peaked at 137.4 Gbps and lasted 68 minutes. Traffic originated from 657 autonomous systems in 19 countries, predominantly residential proxy networks.
| Vector | memcached amplification |
| Peak | 137.4 Gbps |
| Duration | 68 min |
| Time to mitigation | 0.313 s |
| Attack traffic reaching origin | 0.015% |
| Legitimate traffic challenged | 0.45% |
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 17 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.
- Lower challenge thresholds on authentication endpoints during high-risk events.
Our auditors asked for exactly this kind of incident evidence under DORA.
Solid runbook advice. The DNS-at-2am point hit home.
Thanks! Yes — the risk score and its components are included in every log record.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.