Cisco says attackers are already exploiting a new flaw in its Secure Firewall ASA and Secure Firewall Threat Defense software to crash firewalls remotely. If your organisation runs Cisco's SSL remote access VPN, it's worth checking now.

File photo of an older Cisco ASA firewall, 2010. Photo: ShakataGaNai / Wikimedia Commons (CC BY-SA 3.0), cropped