CVE-2016-7797 in Pacemaker
Summary
by MITRE
Pacemaker before 1.1.15, when using pacemaker remote, might allow remote attackers to cause a denial of service (node disconnection) via an unauthenticated connection.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2016-7797 affects Pacemaker clusters version 1.1.14 and earlier, specifically when the pacemaker remote feature is enabled. This issue represents a significant security flaw that could be exploited by remote attackers to disrupt cluster operations through deliberate node disconnection. The vulnerability stems from insufficient authentication mechanisms within the pacemaker remote functionality, which allows unauthorized connections that can manipulate cluster state and potentially cause service interruptions.
The technical flaw lies in the authentication handling within the pacemaker remote component that enables external nodes to connect to the cluster. When pacemaker remote is configured, it creates a communication channel that should require proper authentication to establish connections. However, this vulnerability allows unauthenticated connections to be accepted and processed, which can result in malicious actors establishing connections and triggering node disconnection events. The flaw specifically impacts the cluster's ability to maintain consistent node states and can lead to cascading failures throughout the distributed system.
From an operational impact perspective, this vulnerability creates a severe risk to high availability systems that depend on Pacemaker for cluster management. The denial of service condition can cause complete node disconnections, leading to service disruptions that may affect critical infrastructure components. Attackers can exploit this weakness to systematically disconnect nodes from the cluster, potentially causing partial or complete service outages. The vulnerability particularly affects environments where cluster stability is paramount, such as financial services, telecommunications, and healthcare systems where continuous availability is required.
The security implications extend beyond simple denial of service as this vulnerability can be leveraged as part of broader attack strategies within the MITRE ATT&CK framework, specifically under the T1499 technique for network disruption and T1566 for social engineering. Organizations using affected versions of Pacemaker should prioritize immediate patching to mitigate this risk. The fix involves upgrading to Pacemaker version 1.1.15 or later, which includes proper authentication checks for remote connections. Additionally, network segmentation and firewall rules should be implemented to restrict access to pacemaker remote ports, and monitoring should be enhanced to detect unauthorized connection attempts. Organizations should also review their cluster configurations to ensure that pacemaker remote is only enabled when absolutely necessary and properly secured.
This vulnerability aligns with CWE-287, which addresses improper authentication issues, and demonstrates how weak authentication mechanisms can lead to significant operational disruptions. The flaw represents a classic case of insufficient access control that allows unauthorized entities to manipulate cluster state. Security teams should implement comprehensive monitoring solutions to detect anomalous connection patterns and establish automated alerting for unauthorized access attempts. Regular security assessments and vulnerability scanning should include verification of Pacemaker versions and configuration settings to prevent exploitation of this and similar vulnerabilities. The remediation process should also include reviewing and updating access control policies to ensure that only authorized entities can establish connections to cluster management components.