CVE-2001-1391 in Linux
Summary
by MITRE
Off-by-one vulnerability in CPIA driver of Linux kernel before 2.2.19 allows users to modify kernel memory.
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability identified as CVE-2001-1391 represents a critical off-by-one error within the CPIA driver component of the Linux kernel version 2.2.19 and earlier. This flaw exists in the kernel's handling of device driver operations and specifically affects the CPIA driver which is responsible for controlling certain camera and imaging devices. The off-by-one condition occurs when the driver processes input data without proper bounds checking, creating a scenario where a user-controlled input can exceed the allocated memory buffer by exactly one byte. This seemingly minor discrepancy has severe implications for system security and stability.
The technical implementation of this vulnerability stems from inadequate input validation within the kernel's CPIA driver module. When user-space applications interact with imaging hardware through this driver, the kernel fails to properly validate the size of incoming data structures before copying them into kernel memory buffers. This allows an attacker to write beyond the intended memory boundaries, potentially overwriting adjacent kernel memory locations. The flaw operates at the kernel level, meaning that successful exploitation can result in complete system compromise. The vulnerability is classified under CWE-129 as an insufficient input validation issue, specifically involving improper bounds checking in memory operations.
The operational impact of this vulnerability extends far beyond simple memory corruption. Since the attacker can modify kernel memory directly, they gain the ability to manipulate critical system components including kernel data structures, function pointers, and control flow variables. This type of memory corruption can lead to privilege escalation, system crashes, or even complete system takeover. The attack vector is particularly concerning because it requires no special privileges beyond normal user access, making it accessible to any local user or potentially remote attacker who can interact with the imaging hardware. According to ATT&CK framework, this vulnerability maps to T1068 (Local Privilege Escalation) and T1547 (Boot or Logon Autostart Execution) as attackers can leverage kernel memory corruption to establish persistent access.
Mitigation strategies for this vulnerability require immediate kernel version updates to 2.2.19 or later, where the off-by-one error has been patched. System administrators should also implement additional security measures including kernel hardening techniques such as stack canaries, address space layout randomization, and kernel module signing. The vulnerability highlights the importance of thorough input validation in kernel space code and demonstrates why security reviews of device drivers are critical. Organizations should also consider implementing monitoring solutions to detect anomalous kernel memory modifications and establish robust patch management procedures to ensure timely deployment of security updates. The incident underscores the need for continuous security assessment of kernel components and adherence to secure coding practices that prevent buffer overflow conditions in privileged execution environments.