PAN-OS: Firewall Denial of Service (DoS) via a Burst of Crafted Packets

A memory leak exists in Palo Alto Networks PAN-OS software that enables an attacker to send a burst of crafted packets through the firewall that eventually prevents the firewall from processing traffic. This issue applies only to PA-5400 Series devices that are running PAN-OS software with the SSL Forward Proxy feature enabled.

Work around:
You can mitigate this issue by disabling decryption on your firewalls. To temporarily disable SSL Decryption, refer to the administrator’s guide for your PAN-OS software (such as PAN-OS 11.1: https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-admin/decryption/temporarily-disable-ssl-decryption). Additionally, to ensure that decryption remains disabled after a reboot, configure a policy-based decryption exclusion that excludes all traffic from being decrypted (https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-admin/decryption/decryption-exclusions/create-a-policy-based-decryption-exclusion).