CVE-2016-0721 in PCS
Summary
by MITRE
Session fixation vulnerability in pcsd in pcs before 0.9.157.
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Analysis
by VulDB Data Team • 12/01/2022
The CVE-2016-0721 vulnerability represents a critical session fixation flaw in the pcsd service component of the pcs (Pacemaker Cluster Service) software suite. This vulnerability specifically affects versions prior to 0.9.157 and exposes systems running cluster management services to potential unauthorized access and privilege escalation. The issue stems from the improper handling of session identifiers during authentication processes, creating a scenario where attackers can manipulate session tokens to maintain persistent access to cluster management interfaces. The pcsd service operates as a critical component in high-availability cluster environments, making this vulnerability particularly concerning for enterprise infrastructure relying on cluster management systems. Session fixation vulnerabilities occur when a system fails to generate new session identifiers upon successful authentication, allowing malicious actors to reuse predetermined session tokens. This flaw directly violates security best practices for session management and can be exploited to gain unauthorized administrative control over cluster resources. The vulnerability is classified under CWE-384, which specifically addresses session fixation issues in web applications and services, making it a well-documented weakness in software security architecture.
The technical exploitation of this vulnerability involves an attacker capturing a valid session identifier from a legitimate user session and then using that same identifier to establish their own authenticated session within the same cluster management environment. When pcsd fails to regenerate session tokens upon successful authentication, it maintains the original session identifier, creating a persistent access vector for malicious actors. The flaw becomes particularly dangerous in clustered environments where administrative access to pcsd provides control over critical infrastructure components including resource management, failover operations, and cluster configuration settings. Attackers can leverage this vulnerability to perform unauthorized cluster modifications, initiate resource allocation changes, or even cause service disruptions that impact business continuity. The vulnerability exists in the authentication flow of pcsd, which typically operates on TCP port 3121 and communicates with cluster nodes using specific protocols. This authentication mechanism failure creates a persistent threat that can be exploited across multiple nodes within a cluster, potentially compromising entire infrastructure ecosystems.
The operational impact of CVE-2016-0721 extends beyond simple unauthorized access to encompass broader security implications for enterprise cluster management systems. Organizations using affected versions of pcs may experience unauthorized modifications to cluster configurations, leading to service degradation or complete system failures. The vulnerability can be exploited to gain administrative privileges over cluster resources, potentially enabling attackers to manipulate resource scheduling, alter failover behaviors, or disrupt critical business processes. Given that pcsd typically operates in high-availability environments where cluster integrity is paramount, this vulnerability poses significant risk to business continuity and disaster recovery planning. The attack surface is particularly broad as it affects any organization utilizing Pacemaker cluster services for high-availability solutions, including telecommunications providers, financial institutions, and critical infrastructure operators. The vulnerability can be combined with other attack vectors to create more sophisticated exploitation scenarios, potentially leading to complete system compromise within cluster environments. This type of vulnerability directly impacts the CIA triad by compromising confidentiality, integrity, and availability of cluster management systems.
Mitigation strategies for CVE-2016-0721 require immediate patching of affected pcsd installations to version 0.9.157 or later, which contains the necessary session management fixes. Organizations should also implement network segmentation to limit access to pcsd services, restrict authentication to trusted networks, and enforce strong access controls for cluster management interfaces. Security monitoring should be enhanced to detect unusual authentication patterns or session reuse attempts that may indicate exploitation attempts. System administrators should conduct comprehensive vulnerability assessments of their cluster environments to identify other potential session management weaknesses. The implementation of proper session management practices, including automatic session token regeneration upon authentication, should be enforced across all cluster management services. Additionally, organizations should establish robust incident response procedures specifically addressing cluster management system compromises and implement regular security audits of their high-availability infrastructure. Compliance with industry standards such as those outlined in the NIST SP 800-53 security controls for session management and authentication should be enforced. The vulnerability demonstrates the importance of proper session lifecycle management and highlights the need for continuous security testing of critical infrastructure components. Organizations should also consider implementing additional security controls such as multi-factor authentication for cluster management access and regular security training for personnel responsible for cluster administration. The remediation process should include thorough testing of patched environments to ensure that session management functions properly and that no regression issues have been introduced.