CVE-2004-1014 in nfs-utils
Summary
by MITRE
statd in nfs-utils 1.257 and earlier does not ignore the SIGPIPE signal, which allows remote attackers to cause a denial of service (server process crash) via a TCP connection that is prematurely terminated.
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Analysis
by VulDB Data Team • 06/30/2019
The vulnerability identified as CVE-2004-1014 affects the statd daemon component within nfs-utils version 1.257 and earlier implementations. This daemon serves as a crucial part of the Network File System (NFS) infrastructure responsible for managing client server relationships and maintaining state information about NFS clients. The flaw manifests in how statd handles specific signal interruptions during TCP connection processing, creating a potential attack vector that can be exploited by remote adversaries to disrupt NFS services.
The technical root cause of this vulnerability lies in the improper signal handling mechanism within the statd daemon. Specifically, when the daemon receives a SIGPIPE signal during TCP connection processing, it fails to properly ignore this signal as expected in normal operation. SIGPIPE is typically sent by the operating system when a process attempts to write to a pipe or socket whose reading end has been closed. In the context of NFS operations, this situation can occur when a client prematurely terminates a TCP connection while the server is processing requests. The daemon's failure to properly handle this signal results in an unhandled exception that causes the statd process to crash and terminate unexpectedly.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a significant denial of service attack vector that can be executed remotely without requiring authentication or privileged access. An attacker can exploit this weakness by establishing a TCP connection to the NFS server and then prematurely closing the connection while the server is processing requests. This action triggers the SIGPIPE signal that the daemon cannot properly handle, leading to process termination and subsequent service unavailability. The consequence is that NFS services become inaccessible to legitimate users, potentially causing widespread disruption in networked environments that depend on NFS for file sharing operations.
This vulnerability aligns with CWE-401, which describes the weakness of improper handling of signals during program execution, and represents a classic example of signal handling flaws that can lead to process termination. The attack pattern corresponds to techniques described in the ATT&CK framework under the T1499.004 subtechnique for "Network Denial of Service," where adversaries target specific services to disrupt availability. The vulnerability demonstrates how seemingly minor implementation details in signal handling can create significant security implications, particularly in critical system components like NFS state management daemons. Organizations running affected versions of nfs-utils should immediately implement patches or upgrades to address this issue, as the vulnerability can be exploited by any remote attacker with network access to the affected NFS server, making it a particularly concerning weakness in enterprise network infrastructure.
The broader implications of this vulnerability highlight the importance of proper signal handling in daemon processes and the critical nature of maintaining robust error handling mechanisms in network services. System administrators should ensure that all NFS-related services are updated to versions that properly handle SIGPIPE signals and other potential interruption conditions. Additionally, monitoring systems should be configured to detect process crashes and restart services automatically to minimize the impact of such attacks. This vulnerability serves as a reminder that even minor implementation oversights in system daemons can create significant security risks that affect the availability and reliability of critical network services.