CVE-2016-3656 in PAN-OS
Summary
by MITRE
The GlobalProtect Portal in Palo Alto Networks PAN-OS before 5.0.18, 6.0.x before 6.0.13, 6.1.x before 6.1.10, and 7.0.x before 7.0.5H2 allows remote attackers to cause a denial of service (service crash) via a crafted request.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2016-3656 represents a critical denial of service flaw within the GlobalProtect Portal component of Palo Alto Networks PAN-OS software. This issue affects multiple versions of the firewall operating system, specifically targeting releases before the mentioned patches including 5.0.18, 6.0.13, 6.1.10, and 7.0.5H2. The vulnerability manifests when the system processes specially crafted requests that trigger a service crash, effectively rendering the GlobalProtect Portal unavailable to legitimate users and disrupting secure remote access operations.
The technical nature of this vulnerability stems from inadequate input validation mechanisms within the GlobalProtect Portal's request handling process. When remote attackers submit malformed or crafted requests to the portal service, the system fails to properly sanitize or validate the incoming data, leading to an exploitable condition that causes the service to terminate unexpectedly. This type of vulnerability falls under the category of improper input validation as classified by CWE-20, which specifically addresses weaknesses in software that fail to properly validate or sanitize input data. The flaw essentially allows an attacker to manipulate the application's normal execution flow through carefully constructed payloads that exploit memory handling or state management issues within the portal service.
The operational impact of CVE-2016-3656 extends beyond simple service disruption to potentially compromise the security posture of organizations relying on Palo Alto Networks firewalls for remote access. When the GlobalProtect Portal crashes, legitimate users lose access to corporate resources through the secure remote access solution, creating a significant business continuity issue while simultaneously providing attackers with a means to disrupt authorized network access. This vulnerability directly impacts the availability aspect of the CIA triad and can be categorized under the ATT&CK technique T1499.1 for network denial of service, where attackers exploit weaknesses in network infrastructure to disrupt services. Organizations may experience increased helpdesk tickets, reduced productivity, and potential security gaps if the service disruption is not promptly addressed, as users may seek alternative, potentially less secure methods to access corporate resources.
Mitigation strategies for this vulnerability require immediate deployment of the vendor-provided security patches that address the specific input validation flaws in the GlobalProtect Portal implementation. Organizations should prioritize updating their PAN-OS systems to versions 5.0.18, 6.0.13, 6.1.10, or 7.0.5H2 respectively, depending on their current software version. Network administrators should also implement additional monitoring and intrusion detection measures to identify and block suspicious requests that may attempt to exploit this vulnerability. The remediation process should include comprehensive testing of the patched systems to ensure that the update does not introduce compatibility issues with existing network configurations or applications. Security teams should also review their incident response procedures to prepare for potential exploitation attempts and establish baseline performance metrics for the GlobalProtect Portal to quickly identify service degradation. Additionally, implementing rate limiting and request validation at the network perimeter can provide additional defense in depth against similar vulnerabilities that may exist in other components of the Palo Alto Networks platform.