The US-CERT is warning organisations to harden their networks, because resurgent malware plus the recent publication of powerful exploits proved too hot to ignore.

The organisation says that threats like the a leak of Equation Group Adaptive Security Appliance (ASA) tooling are bad enough by themselves, but warns plenty of organisations are also yet to knock 2015's SYNful Knock on the head, too.

Together, the two attacks should put Cisco users in a state of alert.

US-CERT is not alone in its fears: security outfit Rapid 7 reckons it has found more than 50,000 ASA-susceptible devices, many un-patched..

US-CERT made the warnings about the advanced attacks in an alert this week detailing how the exploits occur and offering admins defensive strategies.

"The rising threat levels place more demands on security personnel and network administrators to protect information systems," US-CERT says.

The agency is also warning of separate ASA attacks in which net scum lure admins to payload websites that exploit a crustier vulnerability (CVE-2014-3393). It says "several reports" of attacks using that malicious code injection in June.

It is also a good time for Juniper NetScreen admins to ensure they have applied recent patches against Equation group exploits.

US-CERT says those who heed its advice should segregate networks and functions; limit unnecessary lateral communications; harden network devices; secure access to infrastructure devices; run management out of band, and validate that hardware is not counterfeit. ®