CVE-2005-0489 in Linux
Summary
by MITRE
The /proc handling (proc/base.c) Linux kernel 2.4 before 2.4.17 allows local users to cause a denial of service via unknown vectors that cause an invalid access of free memory.
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Analysis
by VulDB Data Team • 09/02/2019
The vulnerability identified as CVE-2005-0489 represents a critical memory management flaw within the Linux kernel version 2.4.x series, specifically affecting versions prior to 2.4.17. This issue resides in the /proc handling mechanisms located in the proc/base.c file, which forms a fundamental component of the kernel's virtual filesystem implementation. The /proc filesystem serves as a pseudo-filesystem that provides an interface to kernel data structures, making it essential for system monitoring, debugging, and process management operations. The vulnerability stems from improper handling of memory access patterns when processing certain /proc file operations, creating a scenario where legitimate kernel operations can inadvertently trigger invalid memory access conditions.
The technical flaw manifests through unspecified vectors that lead to invalid access of free memory, a condition that typically occurs when the kernel attempts to read from or write to memory locations that have already been freed and potentially reallocated. This type of vulnerability falls under the category of memory corruption issues, specifically aligning with CWE-416, which describes the use of freed memory condition. When the kernel processes certain /proc operations, it fails to properly validate memory references, allowing an attacker to craft specific input sequences or trigger conditions that cause the kernel to access memory that has been deallocated. This invalid memory access can result in kernel crashes, system instability, or potentially more severe consequences depending on the memory locations being accessed.
From an operational perspective, this vulnerability poses a significant risk to system availability and stability, particularly in environments where local users have access to the system. The denial of service condition can be exploited by any local user with the ability to interact with the /proc filesystem, making it a particularly dangerous vulnerability in multi-user environments or systems where untrusted users might have shell access. The impact extends beyond simple system crashes, as the invalid memory access could potentially lead to information disclosure or privilege escalation opportunities, especially when combined with other vulnerabilities present in the kernel. This vulnerability directly impacts the kernel's ability to maintain consistent state management and could be leveraged by attackers to disrupt critical system services or applications that depend on stable kernel operation.
The exploitation of this vulnerability requires local access and typically involves crafting specific /proc file operations that trigger the memory corruption condition. Attackers can leverage this flaw to repeatedly cause system crashes, leading to persistent denial of service conditions that can be difficult to diagnose and recover from. The vulnerability's impact is amplified by the fact that it affects the core kernel functionality that underpins all system operations, making it particularly dangerous in production environments where system uptime and reliability are paramount. Organizations should consider implementing immediate patching strategies to address this vulnerability, as the risk of exploitation increases with the presence of local users and the complexity of modern system architectures that rely heavily on kernel-level operations for security and functionality. The vulnerability also highlights the importance of thorough kernel testing and validation processes, particularly for memory management subsystems that handle critical system interfaces like the /proc filesystem.
This vulnerability aligns with several ATT&CK framework techniques including privilege escalation and denial of service, as it enables local users to potentially disrupt system operations and could serve as a stepping stone for more sophisticated attacks. The memory corruption aspect of this vulnerability also relates to techniques involving kernel exploitation and system stability compromise, making it relevant to broader cybersecurity threat modeling and incident response procedures. Organizations should ensure that their kernel versions are regularly updated to address such vulnerabilities, as the window of exposure for unpatched systems increases with the complexity and interconnectedness of modern computing environments.