CVE-2016-2363 in Fonality
Summary
by MITRE
Fonality (previously trixbox Pro) 12.6 through 14.1i before 2016-06-01 uses weak permissions for the /var/www/rpc/surun script, which allows local users to obtain root access for unspecified command execution by leveraging access to the nobody account.
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Analysis
by VulDB Data Team • 10/31/2024
The vulnerability identified as CVE-2016-2363 affects Fonality (formerly trixbox Pro) versions 12.6 through 14.1i prior to the 2016-06-01 patch release. This represents a critical privilege escalation flaw that stems from inadequate file permission controls within the application's web infrastructure. The affected system employs the surun script located at /var/www/rpc/surun which serves as a command execution interface for the web application. The weakness lies in the script's improper file permissions that allow unauthorized local users to exploit the system's access controls and escalate privileges to root level access.
The technical exploitation of this vulnerability occurs through the leveraged access to the nobody account, which represents a low-privilege system user typically used for web server processes. This account, despite its limited permissions, provides sufficient access to interact with the vulnerable surun script due to the weak file permissions that grant execute privileges to users other than the intended administrators. The flaw demonstrates a clear violation of the principle of least privilege, where the system allows unauthorized users to execute commands with elevated privileges through the manipulation of file access controls. This vulnerability directly maps to CWE-276, which addresses improper file permissions and inadequate access control mechanisms.
The operational impact of this vulnerability is severe as it provides local attackers with complete system compromise capabilities. Once an attacker gains access to the nobody account, they can execute arbitrary commands with root privileges, enabling them to modify system files, install malicious software, steal sensitive data, or establish persistent backdoors. The vulnerability essentially transforms a low-privilege access point into a root access vector, making it particularly dangerous for systems that host the affected Fonality application. The time-sensitive nature of this vulnerability, with the patch release date of June 1, 2016, indicates that organizations running these versions were exposed to significant risk for an extended period.
Security mitigation strategies for this vulnerability must focus on immediate permission adjustments and access control reinforcement. The primary remediation involves setting appropriate file permissions for the surun script to ensure that only authorized users or system processes can execute it with elevated privileges. Organizations should implement strict access controls for all web application scripts and ensure that file permissions align with the principle of least privilege. Additionally, system administrators should conduct comprehensive audits of file permissions across all web application directories to identify similar weak configurations. The remediation process should also include monitoring for unauthorized access attempts and implementing proper logging mechanisms to track privilege escalation attempts. This vulnerability highlights the importance of regular security assessments and timely patch management as outlined in industry best practices for maintaining secure system configurations.