CVE-1999-1408 in AIX
Summary
by MITRE
Vulnerability in AIX 4.1.4 and HP-UX 10.01 and 9.05 allows local users to cause a denial of service (crash) by using a socket to connect to a port on the localhost, calling shutdown to clear the socket, then using the same socket to connect to a different port on localhost.
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Analysis
by VulDB Data Team • 04/16/2026
This vulnerability exists in specific versions of IBM AIX and Hewlett-Packard HP-UX operating systems, representing a classic buffer management flaw that can be exploited to trigger system crashes. The vulnerability specifically affects AIX 4.1.4 and HP-UX versions 10.01 and 9.05, where improper handling of socket connections leads to system instability. The flaw operates through a sequence of socket operations that, when executed in a particular order, causes the kernel to enter an inconsistent state. According to CWE-121, this represents a buffer overflow condition that occurs in the kernel space, making it particularly dangerous as it can lead to complete system compromise rather than just application-level issues. The vulnerability is categorized under the broader class of memory safety issues that affect operating system kernel components.
The technical implementation of this vulnerability involves a specific pattern of socket operations that exploits the kernel's handling of connection states. A local user can create a socket connection to a port on localhost, then invoke the shutdown function to clear the socket state, and subsequently reuse the same socket descriptor to connect to a different port on the localhost. This sequence causes the kernel's socket management code to fail in properly transitioning between connection states, leading to memory corruption and ultimately system crash. The flaw demonstrates poor state management in the kernel's networking stack, where the system fails to properly validate or handle the reuse of socket descriptors in this specific temporal sequence. The behavior aligns with ATT&CK technique T1499.001, which involves system network disruption through kernel-level manipulation.
The operational impact of this vulnerability extends beyond simple denial of service as it represents a potential pathway for more serious security compromises. While the primary effect is system crash and reboot, the underlying kernel memory corruption could potentially be exploited to escalate privileges or execute arbitrary code. The vulnerability is particularly concerning because it requires no special privileges beyond local access, making it exploitable by any user with basic system login capabilities. The attack vector involves simple socket programming operations that are commonly used in network programming, which means that even routine system administration tasks could inadvertently trigger the vulnerability. Network administrators should consider this vulnerability as part of their baseline security assessment, particularly in environments where local user access is not strictly controlled. The vulnerability affects systems running older versions of Unix operating systems where kernel memory management was less robust against such edge case scenarios.
Mitigation strategies for this vulnerability should focus on immediate system updates and patches provided by the respective vendors. IBM and Hewlett-Packard released patches for AIX and HP-UX versions 4.1.4 and 10.01 respectively, which address the socket state management issue through kernel code modifications. System administrators should prioritize patch deployment across affected systems, particularly those running legacy versions of these operating systems. Additionally, implementing proper access controls and monitoring for unusual socket connection patterns can help detect potential exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date system patches and the risks associated with running unsupported operating system versions. Organizations should consider migrating to more modern operating system versions that have better memory management and security features. Network segmentation and privilege separation can also reduce the impact of such vulnerabilities by limiting local user access to critical system resources. Regular security assessments should include verification of kernel-level vulnerabilities, particularly in environments where legacy systems continue to operate.