CVE-2007-3380 in Linux
Summary
by MITRE
The Distributed Lock Manager (DLM) in the cluster manager for Linux kernel 2.6.15 allows remote attackers to cause a denial of service (loss of lock services) by connecting to the DLM port, which probably prevents other processes from accessing the service.
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Analysis
by VulDB Data Team • 07/29/2019
The Distributed Lock Manager vulnerability identified as CVE-2007-3380 represents a critical flaw in the Linux kernel's cluster management infrastructure that specifically affects kernel versions 2.6.15 and earlier. This vulnerability resides within the Distributed Lock Manager component, which serves as a fundamental building block for coordinating access to shared resources across multiple nodes in a clustered environment. The DLM operates by managing locks and ensuring data consistency in distributed systems, making it a crucial component for maintaining system integrity in high-availability setups. When compromised, this vulnerability can severely impact the operational reliability of clustered Linux systems that depend on proper lock management for their distributed applications.
The technical flaw manifests through an insufficient input validation mechanism within the DLM service implementation. Remote attackers can exploit this weakness by establishing connections to the designated DLM port without proper authentication or authorization checks. The vulnerability stems from the lack of proper connection handling and resource management within the kernel's cluster subsystem, allowing malicious actors to flood the DLM service with connection requests. This particular flaw falls under the category of resource exhaustion attacks, where the attacker's actions consume system resources or service capacity in a manner that prevents legitimate operations from proceeding normally. The DLM's failure to properly validate incoming connections means that any remote entity can potentially disrupt the lock management service by simply connecting to the appropriate network port.
The operational impact of this vulnerability extends far beyond simple service disruption, as it fundamentally compromises the integrity of distributed applications relying on the cluster manager's lock services. When an attacker successfully exploits this vulnerability, they can cause a complete denial of service condition where legitimate processes lose access to critical lock mechanisms that ensure data consistency across the cluster. This can result in cascading failures throughout the distributed system, as applications that depend on proper lock acquisition may become unresponsive or enter inconsistent states. The vulnerability particularly affects environments where multiple nodes must coordinate access to shared storage or resources, making it a significant concern for enterprise-level clustered systems, database clusters, and high-availability server configurations that depend on proper lock management for their operation.
Mitigation strategies for this vulnerability require immediate attention and should include implementing network-level restrictions to limit access to the DLM port, typically located at port 11111 or similar cluster management ports. System administrators should deploy firewall rules to restrict connections to these ports to only trusted management hosts and authorized cluster nodes. Additionally, upgrading to kernel versions 2.6.16 or later is essential as these releases contain patches addressing the DLM connection handling flaws. The vulnerability aligns with CWE-400, which categorizes resource exhaustion issues, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing intrusion detection systems to monitor for unusual connection patterns to cluster management ports and establish proper access controls that enforce authentication requirements before allowing DLM service connections. Regular security audits of cluster configurations and network segmentation practices can help prevent unauthorized access to critical cluster management services.