CVE-2021-3053 in PAN-OS
Summary
by MITRE • 09/09/2021
An improper handling of exceptional conditions vulnerability exists in the Palo Alto Networks PAN-OS dataplane that enables an unauthenticated network-based attacker to send specifically crafted traffic through the firewall that causes the service to crash. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.9; PAN-OS 10.0 versions earlier than PAN-OS 10.0.5. This issue does not affect Prisma Access.
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Analysis
by VulDB Data Team • 09/10/2021
The vulnerability described in CVE-2021-3053 represents a critical improper handling of exceptional conditions flaw within the Palo Alto Networks PAN-OS dataplane architecture. This issue stems from inadequate error processing mechanisms that fail to properly manage malformed or specially crafted network traffic packets. The vulnerability specifically affects the firewall's data processing pipeline where exceptional conditions are not gracefully handled, leading to system instability and potential service disruption. The flaw exists at the core dataplane level, meaning it operates at the fundamental network processing layer where packets are inspected, classified, and forwarded through the firewall's security policies. This represents a fundamental architectural weakness in the PAN-OS implementation that allows attackers to exploit the system's failure to properly handle edge cases in packet processing.
The technical exploitation of this vulnerability occurs through the injection of specifically crafted network traffic that triggers the exceptional condition handling failure. When the firewall receives such malformed packets, the system's internal error handling mechanisms fail to properly terminate the processing thread or gracefully recover from the exceptional state. Instead, the system enters a crash state where critical services become unavailable, forcing the device to restart automatically. This restart process places the firewall into maintenance mode, effectively rendering all network services unavailable and creating a complete denial of service condition for the protected network infrastructure. The vulnerability's impact is amplified by the fact that repeated exploitation attempts can cause multiple restart cycles, prolonging the service disruption and potentially leading to complete system unavailability.
The operational impact of CVE-2021-3053 extends far beyond simple service interruption, as it fundamentally compromises the availability and reliability of network security infrastructure. Organizations relying on affected PAN-OS versions face significant risk of network outages that can last from minutes to hours depending on the restart process and recovery procedures. The vulnerability affects multiple major PAN-OS releases including versions 8.1 through 10.0, indicating a widespread exposure across the product line. Network administrators must contend with the possibility of unauthenticated attackers remotely compromising their security infrastructure without requiring any credentials or privileged access. This makes the vulnerability particularly dangerous as it allows adversaries to exploit the system from outside the network perimeter, potentially disrupting critical business operations and leaving networks vulnerable to further attacks during the recovery period.
The vulnerability aligns with CWE-704 improper exception handling, which specifically addresses situations where programs fail to properly handle exceptional conditions that occur during normal operation. From an adversarial perspective, this issue maps directly to ATT&CK technique T1499.004 for network denial of service, as it enables attackers to cause service disruption through crafted network traffic. Organizations should implement immediate mitigations including applying the vendor patches for PAN-OS versions 8.1.20, 9.0.14, 9.1.9, and 10.0.5 respectively. Network segmentation and access control measures should be enhanced to limit exposure, while monitoring systems should be configured to detect unusual traffic patterns that might indicate exploitation attempts. Additionally, organizations should establish incident response procedures that account for the possibility of complete firewall restarts and ensure backup connectivity measures are available during recovery periods. The vulnerability demonstrates the critical importance of robust error handling in security infrastructure components and highlights the need for comprehensive testing of exceptional condition scenarios in network processing systems.