CVE-2017-13694 in Linux
Summary
by MITRE
The acpi_ps_complete_final_op() function in drivers/acpi/acpica/psobject.c in the Linux kernel through 4.12.9 does not flush the node and node_ext caches and causes a kernel stack dump, which allows local users to obtain sensitive information from kernel memory and bypass the KASLR protection mechanism (in the kernel through 4.9) via a crafted ACPI table.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/18/2024
The vulnerability identified as CVE-2017-13694 resides within the Linux kernel's ACPI (Advanced Configuration and Power Interface) subsystem, specifically in the acpi_ps_complete_final_op() function located in drivers/acpi/acpica/psobject.c. This flaw represents a critical information disclosure issue that affects kernel versions through 4.12.9, with particular impact on systems running kernel versions up to 4.9 where KASLR (Kernel Address Space Layout Randomization) protection mechanisms are vulnerable to bypass. The vulnerability stems from improper memory management practices during ACPI table processing, creating a pathway for local attackers to extract sensitive kernel memory contents through carefully crafted ACPI tables.
The technical root cause of this vulnerability lies in the failure of the acpi_ps_complete_final_op() function to properly flush the node and node_ext caches during ACPI operation completion. These caches contain kernel memory structures that are not adequately cleared or sanitized before the function returns, leaving residual data that can be accessed by malicious actors. When a crafted ACPI table is processed by the vulnerable kernel, the incomplete cache flushing operation results in kernel stack dumps that expose kernel memory contents to local users. This memory exposure includes sensitive information such as kernel addresses, stack pointers, and other confidential data structures that are typically protected from user-space access.
The operational impact of this vulnerability is significant for system security and confidentiality. Local users with access to the system can exploit this flaw to bypass KASLR protection mechanisms, which are designed to randomize kernel memory layout to prevent exploitation of memory corruption vulnerabilities. By extracting kernel memory contents through the stack dump mechanism, attackers can obtain critical information such as kernel base addresses, function pointers, and other memory layout details that would normally be randomized and protected. This information can then be used to facilitate more sophisticated attacks, including privilege escalation, kernel exploitation, or bypassing other security mitigations that rely on memory layout randomization.
The vulnerability aligns with CWE-200 (Information Exposure) and represents a classic case of insufficient memory cleanup in kernel space operations. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and information gathering, where adversaries can leverage local access to extract kernel memory contents and bypass security protections. The flaw demonstrates poor memory management practices in kernel code that fails to properly handle cache invalidation during ACPI table processing, creating persistent memory artifacts that leak sensitive information. Organizations running affected kernel versions should prioritize patching to address this vulnerability, as it provides attackers with a straightforward method to obtain kernel memory contents and undermine fundamental security protections.
Mitigation strategies for this vulnerability include immediate patching of affected kernel versions to 4.13 or later where the issue has been resolved through proper cache flushing implementation. System administrators should also implement additional security measures such as disabling unnecessary ACPI functionality, restricting local user access to systems, and monitoring for suspicious ACPI table loading activities. The fix implemented in patched versions ensures that node and node_ext caches are properly flushed during ACPI operation completion, eliminating the memory leakage that enabled the information disclosure and KASLR bypass capabilities. Organizations should conduct thorough vulnerability assessments to identify systems running affected kernel versions and ensure comprehensive patch deployment across all affected infrastructure.