Cisco Firewalls Under Siege: 2024 Zero-Day Flaws Trigger DoS Attacks on ASA & FTD
In June 2024, Cisco disclosed that two actively exploited zero-day vulnerabilities in its Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) firewalls were being weaponized in the wild. Attackers leveraged these flaws (CVE-2024-20353 and CVE-2024-20359) to trigger repeated reboot loops, effectively causing Denial-of-Service (DoS) on critical network perimeter defenses. Initial exploitation began as targeted zero-days, but attackers quickly adopted the flaws in larger campaigns, dramatically impacting the availability and security of organizations relying on Cisco ASA or FTD devices. The incident underscores a growing trend of targeting infrastructure security devices as a primary attack vector, especially given the rise of ransomware actors and APT groups seeking disruption over data theft. Exploitation of device vulnerabilities for DoS attacks highlights the heightened urgency for rapid patching and robust segmentation in modern enterprise environments.
Kill Chain
