CVE-2020-1997 in PAN-OS
Summary
by MITRE
An open redirection vulnerability in the GlobalProtect component of Palo Alto Networks PAN-OS allows an attacker to specify an arbitrary redirection target away from the trusted GlobalProtect gateway. If the user then successfully authenticates it will cause them to access an unexpected and potentially malicious website. This issue affects: PAN-OS 7.1 versions earlier than 7.1.26; PAN-OS 8.0 versions earlier than 8.0.14.
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Analysis
by VulDB Data Team • 10/17/2020
The vulnerability identified as CVE-2020-1997 represents a critical open redirection flaw within the GlobalProtect component of Palo Alto Networks PAN-OS platforms. This security weakness enables attackers to manipulate the redirection behavior of the system by specifying arbitrary targets that bypass the trusted GlobalProtect gateway. The vulnerability exists in specific versions of PAN-OS software, particularly affecting PAN-OS 7.1 versions prior to 7.1.26 and PAN-OS 8.0 versions prior to 8.0.14, creating a window of exposure for organizations using these affected releases.
The technical implementation of this vulnerability stems from insufficient validation of redirection targets within the GlobalProtect authentication flow. When users attempt to authenticate through the affected system, the authentication process fails to properly verify or sanitize the destination URLs to which users are redirected after successful authentication. This allows malicious actors to craft specially crafted links or authentication requests that redirect users to attacker-controlled domains. The flaw operates at the application layer and specifically impacts the web-based authentication interface of GlobalProtect, where users are typically directed to a login page before being redirected to their intended network resources.
The operational impact of this vulnerability extends beyond simple redirection attacks, creating potential pathways for sophisticated social engineering campaigns and credential theft operations. When authenticated users are redirected to malicious websites, attackers can leverage the trust relationship established with the legitimate GlobalProtect gateway to harvest credentials, deploy malware, or conduct further reconnaissance activities. This vulnerability directly aligns with CWE-601 Open Redirect vulnerability classification and represents a significant concern within the ATT&CK framework under the T1566 credential harvesting and T1071 application layer protocol categories. The attack vector typically involves phishing campaigns where users are tricked into clicking malicious links that exploit this vulnerability, potentially leading to full network compromise.
Organizations affected by this vulnerability should prioritize immediate remediation through the application of the appropriate PAN-OS patches released by Palo Alto Networks. The recommended mitigation strategy involves upgrading to PAN-OS versions 7.1.26 or later for 7.1 releases, and PAN-OS 8.0.14 or later for 8.0 releases, which contain the necessary fixes to address the open redirection flaw. Additionally, network administrators should implement enhanced monitoring of authentication logs and redirection activities to detect potential exploitation attempts. Security teams should also consider implementing additional controls such as URL filtering and web application firewalls to provide defense-in-depth against potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and the need for robust security controls within authentication systems to prevent attackers from leveraging legitimate trust relationships for malicious purposes.