On Saturday 24 July 2021 at 01:47 UTC, a UDP reflection (NTP) targeted a online casino customer in Latin America. The attack peaked at 305.8 Gbps and lasted 132 minutes. Traffic originated from 838 autonomous systems in 51 countries, predominantly compromised cloud VMs.
| Vector | UDP reflection (NTP) |
| Peak | 305.8 Gbps |
| Duration | 132 min |
| Time to mitigation | 0.386 s |
| Attack traffic reaching origin | 0.043% |
| Legitimate traffic challenged | 0.30% |
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 26 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Keep origin IPs out of public DNS history.
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
Solid runbook advice. The DNS-at-2am point hit home.
Good question. We will cover that in a follow-up post.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?