On Monday, January 18th starting at approximately 11:26 AM PST, Pantheon experienced malicious load-generating traffic that caused resource exhaustion on a sufficient portion of Pantheon’s redundant infrastructure to have some uptime impact on 27% of customer sites. Pantheon engineers began mitigations shortly after the malicious traffic was first observed, and all sites were operating normally by 12:34 PM. 

Pantheon is improving its internal processes to detect and resolve such issues faster in the future. Tasks to mitigate such incidents have also been identified and will be prioritized.