New Cisco firewall zero-day exploited to crash SSL VPN devices

What happened?

Cisco released security updates to patch a denial-of-service zero-day in Adaptive Security Appliance (ASA) and Threat Defense (FTD) software that attackers are exploiting to remotely crash vulnerable firewall devices. [...]

Key details

• Cisco issued updates to fix a DoS zero‑day in ASA and FTD firewalls.
• The vulnerability targets ASA/FTD devices that have the ‘webvpn’ keyword and SSL VPN enabled.
• Exploitation lets unauthenticated remote attackers cause the device to reload, creating a denial‑of‑service.
• Cisco warned customers to apply patches after PSIRT saw evidence of wild exploitation.
• CISA issued an emergency directive ordering federal agencies to secure Cisco firewalls within 24 hours.
• The attacks are tied to the ArcaneDoor campaign, which also used other zero‑days against government networks.

Summarised by SecOraLens from BleepingComputer. Always read the original source before acting. How SecOraLens verifies advisories.