CVE-2022-26019 in pfSense CE
Summary
by MITRE • 03/31/2022
Improper access control vulnerability in pfSense CE and pfSense Plus (pfSense CE software versions prior to 2.6.0 and pfSense Plus software versions prior to 22.01) allows a remote attacker with the privilege to change NTP GPS settings to rewrite existing files on the file system, which may result in arbitrary command execution.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 04/02/2022
The CVE-2022-26019 vulnerability represents a critical access control flaw affecting pfSense Community Edition and pfSense Plus systems. This vulnerability exists in versions prior to 2.6.0 for pfSense CE and 22.01 for pfSense Plus, creating a dangerous privilege escalation vector that can lead to complete system compromise. The flaw specifically targets the Network Time Protocol GPS configuration functionality, which is commonly used for time synchronization in network infrastructure devices. The vulnerability's severity stems from the improper validation of file paths during NTP GPS settings modifications, allowing authenticated attackers with limited privileges to manipulate the file system in ways that were never intended by the software design.
The technical implementation of this vulnerability exploits a path traversal flaw within the NTP GPS configuration handler. When users with the specific privilege to modify NTP GPS settings attempt to save configuration changes, the system fails to properly sanitize or validate the file paths used in the underlying file operations. This allows an attacker to specify arbitrary file paths that can overwrite existing system files or create malicious files in critical system directories. The vulnerability operates at the file system level, bypassing normal access controls and permissions mechanisms that should prevent such operations. This flaw aligns with CWE-22 Path Traversal and CWE-73 Path Traversal, both of which are categorized under the broader class of improper input validation issues that enable attackers to manipulate file system operations.
From an operational perspective, this vulnerability presents a significant risk to network infrastructure security since it allows remote attackers to execute arbitrary commands on affected systems. The attack vector requires an authenticated user with the specific privilege to modify NTP GPS settings, which is typically a limited administrative function. However, once exploited, the vulnerability can provide attackers with full system control, enabling them to install backdoors, exfiltrate sensitive data, or disrupt network operations. The impact extends beyond simple privilege escalation as it can be leveraged to establish persistent access to network infrastructure, making it particularly dangerous for organizations relying on pfSense for firewall and routing services. This vulnerability also aligns with ATT&CK technique T1059 Command and Scripting Interpreter, as it enables arbitrary command execution through the compromised file system manipulation.
Organizations affected by this vulnerability should prioritize immediate remediation through official software updates provided by pfSense. The patch addresses the root cause by implementing proper input validation and path sanitization within the NTP GPS configuration handling code. System administrators should also conduct comprehensive security audits to identify any potential exploitation attempts and monitor for unusual file system modifications or command execution patterns. Network segmentation strategies should be reviewed to limit the potential impact of such vulnerabilities, particularly in environments where administrative privileges might be more broadly distributed. Additionally, implementing proper monitoring solutions that can detect anomalous file system operations or configuration changes can help identify exploitation attempts before they result in successful compromise. The vulnerability demonstrates the critical importance of proper access control implementation and input validation in network security appliances, where a single flaw can undermine the security of entire network infrastructures.