CVE-2005-1400 in FreeBSD
Summary
by MITRE
The i386_get_ldt system call in FreeBSD 4.7 to 4.11 and 5.x to 5.4 allows local users to access sensitive kernel memory via arguments with negative or very large values.
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Analysis
by VulDB Data Team • 03/11/2021
The vulnerability identified as CVE-2005-1400 represents a critical memory access flaw within the FreeBSD operating system's i386_get_ldt system call implementation. This issue affects FreeBSD versions ranging from 4.7 through 4.11 and 5.x through 5.4, creating a significant security risk for systems running these kernel versions. The vulnerability stems from inadequate input validation within the system call handler, specifically when processing arguments that contain negative or excessively large values. The technical flaw manifests as a buffer over-read condition that occurs when the system call processes malformed argument values without proper bounds checking, allowing unauthorized memory access that could expose sensitive kernel data to local attackers.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables local users to potentially extract confidential kernel memory contents through carefully crafted system call invocations. Attackers can exploit this weakness by invoking the i386_get_ldt system call with malicious argument values that cause the kernel to traverse memory regions beyond intended boundaries. This behavior creates opportunities for privilege escalation and information gathering attacks, as the leaked kernel memory may contain sensitive data such as cryptographic keys, passwords, or other confidential system information. The vulnerability is particularly concerning because it operates at the kernel level and requires only local user privileges to exploit, making it accessible to any user with system access.
From a cybersecurity perspective, this vulnerability aligns with CWE-129, which describes improper validation of array index values, and represents a classic example of unsafe memory access patterns. The flaw demonstrates poor input validation practices within kernel space code, where the system call handler fails to properly sanitize or validate argument values before processing them. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the kernel execution environment where attackers can manipulate system call arguments to gain unauthorized access to protected memory regions. The vulnerability also relates to defensive code practices that emphasize proper bounds checking and input validation, particularly in system-level code where memory safety is paramount for overall system security.
Mitigation strategies for this vulnerability involve immediate system updates to patched FreeBSD versions that address the input validation issues within the i386_get_ldt system call implementation. System administrators should prioritize patching affected systems to prevent exploitation, as the vulnerability provides a direct path for local users to access sensitive kernel memory. Additionally, implementing proper input validation mechanisms within kernel code and conducting thorough code reviews for similar system call implementations can help prevent similar issues. Network segmentation and privilege separation measures can also reduce the potential impact of exploitation, though the most effective defense remains applying the official security patches provided by FreeBSD. Organizations should also consider monitoring for unusual system call patterns that might indicate exploitation attempts, particularly around the i386_get_ldt system call usage in affected versions.