The Cisco Adaptive Security Appliance (ASA) devices patch should be applied promptly due to active development of CVE-2018-0296  exploits

https://www.zdnet.com/article/cisco-patch-now-attackers-are-exploiting-asa-dos-flaw-to-take-down-security/

After observing attacks on customers, Cisco is telling users to install the fix for a recently disclosed denial-of-service flaw affecting a number of its security appliances.  The flaw, tracked as CVE-2018-0296, was detailed in an advisory on June 6 and affects Cisco ASA Software and Cisco Firepower Threat Defense (FTD) Software.

Vulnerable products include 3000 Series Industrial Security Appliance (ISA), ASA 1000V Cloud Firewall, ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4100 Series Security Appliance, Firepower 9300 ASA Security Module, and FTD Virtual (FTDv).