PAN-OS: Denial-of-Service (DoS) Vulnerability in GlobalProtect Portal and Gateway Interfaces

An improper handling of exceptional conditions vulnerability exists in Palo Alto Networks GlobalProtect portal and gateway interfaces that enables an unauthenticated network-based attacker to send specifically crafted traffic to a GlobalProtect interface that causes the service to stop responding. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode.

Work around:
Enable signatures for Unique Threat IDs 91820 and 91855 on traffic destined for GlobalProtect interfaces to block attacks against CVE-2021-3063.

It is not necessary to enable SSL decryption to detect and block attacks against this issue.