CVE-2001-1399 in Linux
Summary
by MITRE
Certain operations in Linux kernel before 2.2.19 on the x86 architecture copy the wrong number of bytes, which might allow attackers to modify memory, aka "User access asm bug on x86."
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability identified as CVE-2001-1399 represents a critical memory corruption flaw in the linux kernel version 2.2.18 and earlier on x86 architectures. This issue stems from improper byte copying operations within kernel space that can lead to unauthorized memory modifications. The flaw specifically affects the handling of certain assembly operations where the kernel incorrectly calculates or transfers memory segments, creating opportunities for malicious actors to exploit the system's memory management mechanisms. Such vulnerabilities are particularly dangerous because they operate within kernel space where privileges are highest, potentially allowing attackers to gain elevated system access or corrupt critical system resources.
The technical root cause of this vulnerability lies in the kernel's implementation of memory copy operations on x86 platforms, where specific assembly instructions fail to properly handle the number of bytes being transferred during memory operations. This misconfiguration creates a scenario where attackers can manipulate memory contents through carefully crafted operations that exploit the incorrect byte count handling. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow condition, though it manifests more specifically as a memory corruption issue in kernel space operations. The flaw essentially allows for unauthorized memory access patterns that bypass normal kernel protection mechanisms, making it particularly dangerous for system integrity.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with potential pathways to escalate privileges and execute arbitrary code within the kernel context. Attackers can leverage this flaw to overwrite critical kernel data structures, modify system calls, or manipulate memory mappings to achieve unauthorized access to system resources. This vulnerability directly maps to techniques described in the attack pattern taxonomy under ATT&CK matrix domain of privilege escalation and defense evasion. The exposure affects systems running vulnerable kernel versions and can be exploited through various attack vectors including local privilege escalation and potentially remote code execution depending on system configuration and available interfaces.
Mitigation strategies for CVE-2001-1399 primarily involve immediate kernel version upgrades to 2.2.19 or later, which contain the necessary patches to correct the byte copying operations. System administrators should also implement comprehensive monitoring for suspicious memory access patterns and ensure that kernel security modules are properly configured to detect and prevent unauthorized memory modifications. Additional defensive measures include implementing kernel address space layout randomization where available, restricting system access to minimize attack surface, and maintaining regular security updates to address similar vulnerabilities that may exist in other kernel components. The vulnerability highlights the importance of thorough code review for assembly operations and proper memory management practices in kernel development, emphasizing that even seemingly minor implementation errors can result in significant security implications.