CVE-2001-1396 in Linux
Summary
by MITRE
Unknown vulnerabilities in strnlen_user for Linux kernel before 2.2.19, with unknown impact.
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Analysis
by VulDB Data Team • 07/19/2019
The vulnerability identified as CVE-2001-1396 relates to an unknown flaw in the strnlen_user function within the Linux kernel versions prior to 2.2.19. This function serves as a critical component in kernel space operations, specifically designed to calculate the length of strings while ensuring memory safety during user-space interactions. The strnlen_user function acts as a bridge between user-space applications and kernel-space memory management, making it a potential target for exploitation when vulnerabilities exist in its implementation. The affected kernel versions represent a critical period in Linux kernel development where security measures were still evolving and not yet fully matured. This vulnerability falls under the broader category of kernel-level buffer overflows and memory corruption issues that can lead to privilege escalation and system compromise.
The technical nature of this vulnerability stems from improper handling of string length calculations within kernel space when interfacing with user-space memory regions. The strnlen_user function is responsible for determining string boundaries while safely accessing memory that originates from user-space applications. When this function fails to properly validate or sanitize input parameters, it can lead to memory access violations that may be exploited by malicious actors. The vulnerability likely involves insufficient bounds checking or improper validation of memory addresses that could allow attackers to manipulate kernel memory structures. This type of flaw typically manifests when the kernel fails to properly validate the length of strings being processed, potentially allowing for buffer overflows or information disclosure. The impact is particularly severe because kernel-level vulnerabilities can provide attackers with elevated privileges and full system control. According to CWE classification, this vulnerability would likely map to CWE-121 for buffer overflow conditions or CWE-125 for out-of-bounds read errors, both of which are fundamental memory safety issues.
The operational impact of CVE-2001-1396 extends beyond simple exploitation capabilities, affecting system stability, data integrity, and overall security posture of affected Linux systems. Systems running kernel versions before 2.2.19 would be particularly vulnerable to attacks that leverage this flaw, potentially allowing unauthorized users to escalate privileges from user-level to kernel-level access. The vulnerability could enable attackers to execute arbitrary code with the highest system privileges, effectively compromising the entire system. Additionally, the unknown nature of the specific impact makes this vulnerability particularly dangerous as administrators cannot fully assess the potential damage or plan appropriate defenses. This type of vulnerability could also lead to denial of service conditions, system crashes, or information leakage that could be exploited in conjunction with other attacks. The ATT&CK framework would categorize this vulnerability under privilege escalation techniques, specifically targeting kernel-level access and memory manipulation as part of the adversary's attack chain.
Mitigation strategies for CVE-2001-1396 primarily focus on immediate kernel version upgrades to 2.2.19 or later, which contain the necessary patches to address the strnlen_user function implementation. System administrators should prioritize updating their kernel versions and conducting thorough testing to ensure compatibility with existing applications and services. The patching process should include comprehensive security assessments to verify that no other similar vulnerabilities exist in the kernel or related components. Additional protective measures include implementing kernel security modules such as SELinux or AppArmor to provide additional layers of protection, disabling unnecessary kernel features that might expose the vulnerable function, and monitoring system logs for suspicious activities that could indicate exploitation attempts. Network segmentation and access controls should be reinforced to limit potential attack vectors, while regular security audits should be conducted to identify any remaining vulnerabilities in the system architecture. The vulnerability also underscores the importance of maintaining up-to-date security patches and implementing robust vulnerability management processes to prevent similar issues from occurring in the future.