CVE-2002-1668 in HP-UX
Summary
by MITRE
HP-UX 11.11 and earlier allows local users to cause a denial of service (kernel deadlock), due to a "file system weakness" that is possibly via an mmap() system call and performing an I/O operation using data from the mapped buffer on the file descriptor for the mapped file.
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Analysis
by VulDB Data Team • 03/14/2017
The vulnerability identified as CVE-2002-1668 represents a critical kernel-level weakness in HP-UX operating systems version 11.11 and earlier, specifically targeting the file system implementation and memory management subsystems. This flaw manifests as a potential for local users to trigger kernel deadlocks through improper handling of memory-mapped file operations, creating a denial of service condition that can severely impact system availability and stability.
The technical exploitation of this vulnerability occurs through the manipulation of the mmap() system call combined with subsequent I/O operations on the same file descriptor. When a local user creates a memory mapping of a file and then performs I/O operations using data from the mapped buffer, the kernel's file system handling routines encounter a race condition or deadlock scenario. The underlying issue stems from inadequate synchronization mechanisms within the kernel's file system layer when processing memory-mapped file operations, particularly when multiple concurrent operations are performed on the same file descriptor. This weakness allows for a specific sequence of operations that can cause the kernel's file system subsystem to enter an unrecoverable state where threads become blocked indefinitely, effectively rendering the system unresponsive to file system operations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially compromise the entire system stability and availability. Local users with minimal privileges can exploit this weakness to cause kernel deadlocks that may require system reboot to resolve, disrupting normal operations and potentially affecting critical business processes. The vulnerability is particularly concerning because it operates at the kernel level, making it difficult to detect and mitigate without system-level intervention. The weakness affects the fundamental file system operations that most applications depend upon, meaning that any process attempting to access files through memory mapping could trigger the deadlock condition.
From a cybersecurity perspective, this vulnerability aligns with CWE-116, which addresses improper handling of synchronization in kernel-level operations, and demonstrates characteristics consistent with ATT&CK technique T1499.004 for network denial of service. The vulnerability also relates to CWE-362, which covers concurrent execution issues, particularly race conditions in kernel operations. The exploitability of this weakness requires local access, making it less severe from an external threat perspective but still critical for system administrators to address. The root cause lies in the insufficient validation and synchronization mechanisms within the HP-UX kernel's file system implementation, where the mmap() system call and I/O operations are not properly coordinated to prevent deadlock conditions.
Mitigation strategies for this vulnerability should include immediate patching of affected HP-UX systems to version 11.12 or later, which contains the necessary kernel fixes to address the file system weakness. System administrators should also implement monitoring for suspicious memory mapping activities and I/O operations that could indicate attempted exploitation. Additionally, access controls should be enforced to limit local user privileges where possible, and regular system updates should be maintained to prevent similar vulnerabilities from being exploited. The vulnerability serves as a reminder of the critical importance of proper kernel-level synchronization and the potential for seemingly minor implementation flaws to cause significant system-wide disruptions.