GlobalProtect App: Missing certificate validation vulnerability can disclose pre-logon authentication cookie

When the pre-logon feature is enabled, a missing certification validation in Palo Alto Networks GlobalProtect app can disclose the pre-logon authentication cookie to a man-in-the-middle attacker on the same local area network segment with the ability to manipulate ARP or to conduct ARP spoofing attacks. This allows the attacker to access the GlobalProtect Server as allowed by configured Security rules for the ‘pre-login’ user. This access may be limited compared to the network access of regular users.

Work around:
The impact of this vulnerability can be mitigated by decreasing the allowed timeout settings for the prelogon feature or by completely disabling the feature in the GlobalProtect gateway.