Palo Alto Networks Security Advisories / CVE-2020-2033

CVE-2020-2033 GlobalProtect App: Missing certificate validation vulnerability can disclose pre-logon authentication cookie

Severity 5.3 · MEDIUM
Attack Complexity HIGH
Confidentiality Impact HIGH
Privileges Required NONE
Integrity Impact NONE
User Interaction NONE
Availability Impact NONE


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.

This issue affects:

GlobalProtect app 5.0 versions earlier than GlobalProtect app 5.0.10 when the prelogon feature is enabled;

GlobalProtect app 5.1 versions earlier than GlobalProtect app 5.1.4 when the prelogon feature is enabled.

Product Status

GlobalProtect App 5.1< 5.1.4>= 5.1.4
GlobalProtect App 5.0< 5.0.10>= 5.0.10


CVSSv3.1 Base Score:5.3 (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N)

Weakness Type

CWE-290 Authentication Bypass by Spoofing

CWE-295 Improper Certificate Validation


This issue is fixed in GlobalProtect app 5.0.10, GlobalProtect app 5.1.4, and all later GlobalProtect app versions.

Workarounds and Mitigations

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.


Palo Alto Networks thanks Tom Wyckhuys and Nabeel Ahmed from NTT Belgium for discovering and reporting this issue.


Initial publication
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