CVE-2020-2011 in PAN-OS
Summary
by MITRE
An improper input validation vulnerability in the configuration daemon of Palo Alto Networks PAN-OS Panorama allows for a remote unauthenticated user to send a specifically crafted registration request to the device that causes the configuration service to crash. Repeated attempts to send this request result in denial of service to all PAN-OS Panorama services by restarting the device and putting it into maintenance mode. This issue affects: All versions of PAN-OS 7.1, PAN-OS 8.0; PAN-OS 8.1 versions earlier than 8.1.14; PAN-OS 9.0 versions earlier than 9.0.7; PAN-OS 9.1 versions earlier than 9.1.0.
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Analysis
by VulDB Data Team • 10/17/2020
This vulnerability resides within the configuration daemon of Palo Alto Networks PAN-OS Panorama platform, representing a critical improper input validation flaw that enables remote unauthenticated attackers to execute a denial of service attack against affected systems. The vulnerability specifically manifests when a malicious actor sends a carefully crafted registration request to the device, which triggers an unhandled exception in the configuration service. This flaw operates at the application layer and leverages the device's trust model for incoming registration requests without adequate input sanitization or validation checks. The configuration daemon processes these requests without proper boundary verification, allowing malformed input to propagate through the system's processing pipeline and ultimately cause a service crash.
The technical exploitation of this vulnerability follows a well-defined pattern where the attacker crafts a registration request containing malformed data that bypasses normal input validation mechanisms. This allows the configuration service to process invalid data structures, leading to memory corruption or stack overflow conditions that result in immediate service termination. The vulnerability affects multiple major versions of PAN-OS including 7.1, 8.0, 8.1 (versions prior to 8.1.14), 9.0 (versions prior to 9.0.7), and 9.1 (versions prior to 9.1.0), indicating a widespread impact across the product line. The flaw is classified as a CWE-20: Improper Input Validation, which directly maps to the weakness in input validation that allows attackers to manipulate system behavior through malformed data inputs. This weakness is particularly dangerous as it allows unauthenticated remote exploitation, meaning no credentials are required to attempt the attack.
The operational impact of this vulnerability extends beyond simple service disruption to include complete system unavailability through device restarts and maintenance mode activation. When exploited repeatedly, the vulnerability can force the device into a continuous restart cycle, effectively rendering the entire PAN-OS Panorama infrastructure unavailable for legitimate administrative tasks. This creates a cascading effect where network security policies cannot be managed, monitored, or updated, leaving the organization's network exposure vulnerable to other threats. The attack vector operates over the network without requiring authentication, making it particularly attractive to threat actors seeking to disrupt critical security infrastructure. The vulnerability's impact aligns with ATT&CK technique T1499.004: Network Denial of Service, where adversaries target network infrastructure to disrupt operations and availability of services.
Organizations affected by this vulnerability should prioritize immediate remediation through official PAN-OS patches and updates provided by Palo Alto Networks. The recommended mitigation strategy involves applying the specific security patches that address the input validation weakness in the configuration daemon, particularly for versions 8.1.14, 9.0.7, and 9.1.0 and later. Network segmentation and access controls should be implemented to limit exposure of Panorama devices to untrusted networks, while monitoring solutions should be deployed to detect anomalous registration request patterns. The configuration daemon should be audited for proper input validation mechanisms, and logging should be enhanced to capture registration attempts for forensic analysis. Additionally, implementing rate limiting on registration services can help mitigate repeated attack attempts, and regular vulnerability assessments should be conducted to identify similar input validation weaknesses in other system components. This vulnerability demonstrates the critical importance of input validation in security-critical services and the potential for seemingly minor validation flaws to result in complete system compromise.