Threat Bulletin 1255: UDP reflection (NTP) against a B2B SaaS platform in North America

On Sunday 14 December 2025 at 09:23 UTC, a UDP reflection (NTP) targeted a B2B SaaS customer in North America. The attack peaked at 326.9 Gbps and lasted 116 minutes. Traffic originated from 1462 autonomous systems in 65 countries, predominantly mobile carrier ranges.

Vector UDP reflection (NTP)
Peak 326.9 Gbps
Duration 116 min
Time to mitigation 0.877 s
Attack traffic reaching origin 0.033%
Legitimate traffic challenged 0.47%

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 28 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

  • Enable authenticated origin pulls.
  • Keep origin IPs out of public DNS history.
  • Enable log streaming to your SIEM for faster correlation.

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