https://www.bleepingcomputer.com/news/security/cisco-security-appliances-targeted-for-dos-attacks-via-old-bug/

A critical vulnerability fixed in mid-2018 has been resurrected recently in denial-of-service and information disclosure attempts against Cisco's appliances Adaptive Security (ASA) and Firepower.

The company is issuing a warning to its customers urging them to follow recommendations for proper mitigation actions.