CVE-2020-1995 in PAN-OS
Summary
by MITRE
A NULL pointer dereference vulnerability in Palo Alto Networks PAN-OS allows an authenticated administrator to send a request that causes the rasmgr daemon 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 affects: PAN-OS 9.1 versions earlier than 9.1.2.
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Analysis
by VulDB Data Team • 10/17/2020
The vulnerability described in CVE-2020-1995 represents a critical NULL pointer dereference flaw within the rasmgr daemon of Palo Alto Networks PAN-OS operating system. This daemon is responsible for managing various system services and configurations within the firewall appliance, making its stability essential for overall system operation. The vulnerability specifically affects PAN-OS version 9.1 prior to 9.1.2, indicating a targeted issue within a particular release branch that required immediate attention from security teams and system administrators. The flaw manifests when an authenticated administrator sends a specially crafted request to the system, triggering the daemon to attempt to access a NULL memory pointer, which results in an immediate crash of the rasmgr process.
The technical nature of this vulnerability aligns with CWE-476, which classifies NULL pointer dereference as a common programming error that occurs when a program attempts to access memory through a pointer that has not been properly initialized or has been set to NULL. This type of vulnerability typically arises from insufficient input validation and error handling within the application code, particularly in daemon processes that handle administrative requests. The rasmgr daemon's failure to properly validate or sanitize incoming requests from authenticated administrators creates a condition where malicious or malformed input can cause the system to crash. The vulnerability's exploitation requires only authentication privileges, making it particularly dangerous as it can be leveraged by insiders or compromised accounts with administrative access to the system.
The operational impact of CVE-2020-1995 extends beyond a simple service disruption to create a complete system outage scenario. When the rasmgr daemon crashes, it triggers a cascading failure that affects all PAN-OS services running on the device, effectively bringing the entire firewall appliance to a halt. The system automatically restarts itself to recover from the crash, but this recovery process places the device into maintenance mode, rendering it completely non-functional for network security operations. This denial of service condition can severely impact network security posture, as the firewall becomes unavailable to enforce security policies, filter traffic, and provide essential network protection services. The requirement for repeated attempts to achieve the denial of service effect suggests that the vulnerability may be exploitable through automated scripts, potentially allowing for rapid system degradation.
Organizations affected by this vulnerability should implement immediate mitigations including applying the vendor-provided security update that addresses the NULL pointer dereference in the rasmgr daemon. The patch released by Palo Alto Networks for PAN-OS 9.1.2 resolves the underlying issue by adding proper input validation and error handling within the daemon's request processing logic. Additionally, system administrators should consider implementing network segmentation and access controls to limit administrative access to only trusted personnel, thereby reducing the attack surface for this particular vulnerability. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service, as it allows an authenticated user to escalate their privileges to cause system-wide disruption. The vulnerability also highlights the importance of secure coding practices and proper memory management in daemon processes, particularly those handling administrative requests, as outlined in various cybersecurity frameworks and standards such as those recommended by NIST and ISO 27001 for secure system development lifecycle practices.