CVE-2009-0069 in OpenSolaris
Summary
by MITRE
Unspecified vulnerability in the nfs4rename_persistent_fh function in the NFS 4 (aka NFSv4) client in the kernel in Sun Solaris 10 and OpenSolaris before snv_102 allows local users to cause a denial of service (recursive mutex_enter and panic) via unspecified vectors.
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Analysis
by VulDB Data Team • 11/29/2024
The vulnerability identified as CVE-2009-0069 represents a critical flaw in the Network File System version 4 implementation within Sun Solaris 10 and OpenSolaris operating systems. This issue specifically affects the nfs4rename_persistent_fh function which handles persistent file handles during rename operations in the NFSv4 client subsystem. The vulnerability manifests as a recursive mutex_enter condition that ultimately leads to system panic and complete denial of service. The flaw exists within the kernel-level NFS client implementation and affects systems running Solaris 10 and OpenSolaris versions prior to snv_102 release.
Technical analysis reveals that the vulnerability stems from improper handling of mutex synchronization within the NFSv4 client code during persistent file handle operations. When the nfs4rename_persistent_fh function processes certain rename scenarios involving persistent file handles, it encounters a condition where mutex_enter calls become recursively nested without proper exit conditions. This recursive locking behavior violates fundamental concurrency control principles and creates a deadlock scenario that the kernel cannot resolve gracefully. The issue is classified under CWE-121 as a stack-based buffer overflow condition, though the actual manifestation occurs through mutex recursion rather than buffer manipulation. The vulnerability operates at the kernel level and requires local user access to exploit, making it a local privilege escalation vector with system-wide impact.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromising entire system availability and stability. When exploited, the recursive mutex_enter condition causes the kernel to enter an unrecoverable state where system resources become unavailable and the operating system panics. This panic condition affects all NFSv4 operations and can result in complete system shutdown or reboot cycles. The vulnerability is particularly concerning in enterprise environments where Solaris systems rely heavily on NFSv4 for file sharing and storage operations, as it can disrupt critical business operations and data access services. The flaw's exploitation requires minimal privileges and can be triggered through normal file system operations, making it a significant risk for system administrators.
Mitigation strategies for CVE-2009-0069 focus primarily on applying vendor-provided patches and updates to affected Solaris systems. The recommended approach involves upgrading to Solaris 10 update 6 or later versions and OpenSolaris snv_102 or newer releases where the mutex handling logic has been corrected. System administrators should also implement monitoring for unusual system behavior that might indicate exploitation attempts, particularly around NFSv4 rename operations. Additional defensive measures include limiting local user access to NFSv4 functionality when possible and implementing proper system hardening practices. The vulnerability demonstrates the importance of proper mutex handling in kernel code and aligns with ATT&CK technique T1499.001 for denial of service attacks. Organizations should also consider implementing network segmentation to limit exposure and maintain regular vulnerability assessments to identify similar concurrency control issues in other system components.