Description

When Security Assertion Markup Language (SAML) authentication is enabled and the 'Validate Identity Provider Certificate' option is disabled (unchecked), improper verification of signatures in PAN-OS SAML authentication enables an unauthenticated network-based attacker to access protected resources. The attacker must have network access to the vulnerable server to exploit this vulnerability. This issue affects PAN-OS 9.1 versions earlier than PAN-OS 9.1.3; PAN-OS 9.0 versions earlier than PAN-OS 9.0.9; PAN-OS 8.1 versions earlier than PAN-OS 8.1.15, and all versions of PAN-OS 8.0 (EOL). This issue does not affect PAN-OS 7.1. This issue cannot be exploited if SAML is not used for authentication. This issue cannot be exploited if the 'Validate Identity Provider Certificate' option is enabled (checked) in the SAML Identity Provider Server Profile. Resources that can be protected by SAML-based single sign-on (SSO) authentication are: GlobalProtect Gateway, GlobalProtect Portal, GlobalProtect Clientless VPN, Authentication and Captive Portal, PAN-OS next-generation firewalls (PA-Series, VM-Series) and Panorama web interfaces, Prisma Access In the case of GlobalProtect Gateways, GlobalProtect Portal, Clientless VPN, Captive Portal, and Prisma Access, an unauthenticated attacker with network access to the affected servers can gain access to protected resources if allowed by configured authentication and Security policies. There is no impact on the integrity and availability of the gateway, portal or VPN server. An attacker cannot inspect or tamper with sessions of regular users. In the worst case, this is a critical severity vulnerability with a CVSS Base Score of 10.0 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N). In the case of PAN-OS and Panorama web interfaces, this issue allows an unauthenticated attacker with network access to the PAN-OS or Panorama web interfaces to log in as an administrator and perform administrative actions. In the worst-case scenario, this is a critical severity vulnerability with a CVSS Base Score of 10.0 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H). If the web interfaces are only accessible to a restricted management network, then the issue is lowered to a CVSS Base Score of 9.6 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H). Palo Alto Networks is not aware of any malicious attempts to exploit this vulnerability.

Severity

 

CVSS Version 3.x CVSS Version 2.0

CVSS 3.x Severity and Metrics:

CNA:  Palo Alto Networks, Inc.

Base Score:  10.0 CRITICAL

Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: The NVD and the CNA have provided the same score. When this occurs only the CNA information is displayed, but the Acceptance Level icon for the CNA is given a checkmark to signify NVD concurrence.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score:  9.3 HIGH

Vector:  (AV:N/AC:M/Au:N/C:C/I:C/A:C)

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink	Resource
https://security.paloaltonetworks.com/CVE-2020-2021	Vendor Advisory

This CVE is in CISA's Known Exploited Vulnerabilities Catalog

Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.

Vulnerability Name	Date Added	Due Date	Required Action
Palo Alto Networks PAN-OS Authentication Bypass Vulnerability	03/25/2022	04/15/2022	Apply updates per vendor instructions.

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-347	Improper Verification of Cryptographic Signature	NIST   Palo Alto Networks, Inc.

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Initial Analysis by NIST 7/06/2020 10:39:55 AM

Action	Type	Old Value	New Value
Added	CPE Configuration		OR *cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:* versions from (including) 8.0.0 up to (including) 8.0.20 *cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:* versions from (including) 8.1.0 up to (excluding) 8.1.15 *cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:* versions from (including) 9.0.0 up to (excluding) 9.0.9 *cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:* versions from (including) 9.1.0 up to (excluding) 9.1.3
Added	CVSS V2		NIST (AV:N/AC:M/Au:N/C:C/I:C/A:C)
Added	CVSS V3.1		NIST AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Added	CWE		NIST CWE-347
Changed	Reference Type	https://security.paloaltonetworks.com/CVE-2020-2021 No Types Assigned	https://security.paloaltonetworks.com/CVE-2020-2021 Vendor Advisory

CVE Modified by Palo Alto Networks, Inc. 6/29/2020 12:15:10 PM

Action	Type	Old Value	New Value
Changed	Description	Record truncated, showing 500 of 2402 characters. View Entire Change Record When Security Assertion Markup Language (SAML) authentication is enabled and the 'Validate Identity Provider Certificate' option is disabled (unchecked), improper verification of signatures in PAN-OS SAML authentication enables an unauthenticated network-based attacker to access protected resources. The attacker must have network access to the vulnerable server to exploit this vulnerability. This issue affects PAN-OS 9.1 versions earlier than PAN-OS 9.1.3; PAN-OS 9.0 versions earlier than PAN-O	Record truncated, showing 500 of 2380 characters. View Entire Change Record When Security Assertion Markup Language (SAML) authentication is enabled and the 'Validate Identity Provider Certificate' option is disabled (unchecked), improper verification of signatures in PAN-OS SAML authentication enables an unauthenticated network-based attacker to access protected resources. The attacker must have network access to the vulnerable server to exploit this vulnerability. This issue affects PAN-OS 9.1 versions earlier than PAN-OS 9.1.3; PAN-OS 9.0 versions earlier than PAN-OS