CVE-2001-1185 in FreeBSD
Summary
by MITRE
Some AIO operations in FreeBSD 4.4 may be delayed until after a call to execve, which could allow a local user to overwrite memory of the new process and gain privileges.
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Analysis
by VulDB Data Team • 08/18/2024
The vulnerability described in CVE-2001-1185 represents a critical race condition in the FreeBSD 4.4 operating system's handling of asynchronous I/O operations. This flaw occurs within the kernel's interaction between AIO subsystem and process execution mechanisms, creating a window where memory corruption can occur during the transition from one process to another. The issue stems from improper synchronization between AIO completion events and the execve system call that loads a new program into memory. When a process initiates AIO operations and subsequently calls execve, the kernel may defer completion of these operations until after the new process has been loaded, potentially allowing the original process to overwrite memory structures that are subsequently used by the newly executed program.
This vulnerability specifically exploits a timing issue where AIO operations that are in progress or pending completion are not properly synchronized with the process execution context. The flaw allows a local attacker to manipulate the execution flow and potentially corrupt memory locations that will be accessed by the new process after execve completes. The race condition occurs because the kernel does not adequately ensure that all AIO operations are either completed or canceled before proceeding with process execution. This creates an opportunity for privilege escalation attacks where malicious code could overwrite critical memory structures, potentially leading to arbitrary code execution with elevated privileges.
The operational impact of this vulnerability is significant for systems running FreeBSD 4.4, as it provides a local attacker with a method to gain privileges through carefully crafted AIO operations and process execution sequences. The attack requires local access to the system but can result in complete system compromise if successful. The vulnerability affects the integrity and confidentiality of the system, as an attacker could potentially overwrite memory containing sensitive data or executable code. This type of vulnerability is particularly dangerous in multi-user environments where local users might attempt to exploit it to gain elevated privileges and access resources they should not normally be able to reach.
From a security perspective, this vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and represents a classic example of improper synchronization in kernel space operations. The flaw also maps to ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities, and T1059, which involves the use of system calls for code execution. The vulnerability demonstrates how complex interactions between kernel subsystems can create unexpected security implications. Mitigation strategies include upgrading to a newer FreeBSD version where this race condition has been addressed, implementing proper kernel memory protection mechanisms, and applying security patches that ensure AIO operations are properly synchronized with process execution contexts. System administrators should also consider monitoring for unusual AIO activity patterns and implementing additional access controls to limit local user capabilities that could be exploited through such vulnerabilities.