CVE-2017-13693 in Linux
Summary
by MITRE
The acpi_ds_create_operands() function in drivers/acpi/acpica/dsutils.c in the Linux kernel through 4.12.9 does not flush the operand cache 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.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/18/2024
The vulnerability identified as CVE-2017-13693 resides within the Linux kernel's ACPI subsystem, specifically in the acpi_ds_create_operands() function located in drivers/acpi/acpica/dsutils.c. This flaw represents a critical information disclosure vulnerability that affects Linux kernel versions through 4.12.9, with particular severity in versions up to 4.9 where KASLR protection can be bypassed. The vulnerability stems from improper memory management practices within the ACPI table processing pipeline, where the kernel fails to properly flush the operand cache during ACPI table operand creation operations. This oversight creates a condition where sensitive kernel memory contents can be accessed through carefully crafted ACPI tables, exposing the underlying kernel memory layout and potentially enabling attackers to extract critical information that would normally be protected by kernel memory management protections.
The technical exploitation of this vulnerability occurs through the manipulation of ACPI tables, which are used by the operating system to communicate with hardware components and manage system power states. When a maliciously crafted ACPI table is processed by the kernel, the acpi_ds_create_operands() function does not properly clear or reset the operand cache, allowing previously cached operand data to remain accessible in kernel memory. This cache pollution creates a situation where attackers can potentially read kernel memory contents through information leakage mechanisms, including the exposure of kernel virtual addresses, function pointers, and other sensitive data structures. The vulnerability specifically impacts the KASLR (Kernel Address Space Layout Randomization) protection mechanism, which relies on the unpredictability of kernel memory layout to prevent attackers from easily determining the locations of kernel functions and data structures.
From an operational impact perspective, this vulnerability poses significant risks to systems running affected Linux kernel versions, particularly in server environments or embedded systems where ACPI tables may be processed from untrusted sources. Local attackers with the ability to submit or modify ACPI tables can exploit this weakness to bypass KASLR protection, which is a fundamental security mitigation designed to randomize kernel memory layout and prevent exploitation of other kernel vulnerabilities. The information disclosure aspect of this vulnerability enables attackers to gather intelligence about the kernel memory layout, which can be leveraged to improve subsequent exploitation attempts against other kernel vulnerabilities. The vulnerability affects systems where ACPI tables are processed, including those that may receive tables from hardware components, firmware updates, or user-space applications that can influence ACPI table generation, making it particularly dangerous in environments where such table manipulation is possible.
Mitigation strategies for CVE-2017-13693 focus primarily on kernel updates to versions that contain the necessary patches addressing the operand cache flushing issue. The fix implemented in patched kernel versions ensures that the acpi_ds_create_operands() function properly flushes the operand cache before processing new operands, preventing the leakage of cached data into kernel memory spaces accessible to local users. Organizations should prioritize updating their systems to kernel versions that include the specific patches addressing this vulnerability, particularly those that have been released by the Linux kernel security team. Additionally, system administrators should consider implementing additional security measures such as disabling unnecessary ACPI functionality when not required, monitoring for unusual ACPI table processing activities, and ensuring that ACPI tables originate from trusted sources. The vulnerability aligns with CWE-248, which describes an "Uncaught Exception" where an exception is not properly handled, and relates to ATT&CK technique T1068, which involves the exploitation of legitimate credentials and privileges to gain unauthorized access to system resources. The vulnerability also demonstrates characteristics of privilege escalation through information disclosure, making it a critical concern for system administrators who must maintain the security of their kernel-level components.