CVE-2000-0508 in Linux
Summary
by MITRE
rpc.lockd in red hat linux 6.1 and 6.2 allows remote attackers to cause a denial of service via a malformed request.
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Analysis
by VulDB Data Team • 11/02/2024
The vulnerability identified as CVE-2000-0508 affects the rpc.lockd service in Red Hat Linux versions 6.1 and 6.2, representing a significant denial of service weakness within the network file system infrastructure. This issue specifically targets the Network File System (NFS) implementation where rpc.lockd manages file locking operations between clients and servers. The flaw manifests when the service receives malformed requests that it cannot properly process or validate, leading to system instability and potential service disruption. This vulnerability operates at the kernel level within the NFS locking mechanism, making it particularly dangerous as it can affect the entire file sharing infrastructure of affected systems.
The technical implementation of this vulnerability stems from inadequate input validation within the rpc.lockd daemon, which fails to properly sanitize incoming network requests. When remote attackers send malformed requests to the affected service, the daemon experiences unexpected behavior that can result in system crashes or resource exhaustion. This type of flaw falls under the category of improper input validation as classified by CWE-20, where the system does not adequately validate the format and content of received data. The vulnerability specifically relates to the handling of network protocol messages that should be processed according to the NFS version 2 and 3 specifications, but the implementation fails to account for malformed packet structures that could cause buffer overflows or state machine corruption.
From an operational perspective, this vulnerability presents a substantial risk to enterprise environments that rely heavily on NFS file sharing services. Organizations running Red Hat Linux 6.1 or 6.2 systems with active NFS services become vulnerable to remote denial of service attacks that can disrupt critical business operations. The impact extends beyond simple service interruption as the affected systems may require manual intervention to restore normal operations, potentially leading to extended downtime and productivity losses. Attackers can exploit this weakness without requiring authentication credentials, making it particularly attractive for malicious actors seeking to disrupt network services. The vulnerability aligns with ATT&CK technique T1499.004, which involves network disruption through denial of service attacks against network infrastructure.
The mitigation strategies for CVE-2000-0508 primarily involve applying the vendor-supplied security patches that address the input validation issues within rpc.lockd. Red Hat released updated packages for both Linux 6.1 and 6.2 that properly validate incoming requests and handle malformed data gracefully. System administrators should also consider implementing network-level restrictions to limit access to NFS services, particularly disabling unnecessary ports or implementing firewall rules that restrict rpc.lockd access to trusted networks only. Additional defensive measures include monitoring network traffic for suspicious patterns and implementing intrusion detection systems that can identify malformed requests targeting NFS services. The vulnerability demonstrates the critical importance of proper input validation and robust error handling in network services, as outlined in security best practices for preventing similar issues in modern implementations. Organizations should also consider upgrading to more recent versions of Red Hat Linux that contain improved security controls and better protection against such vulnerabilities.