CVE-2017-1084 in FreeBSD
Summary
by MITRE
In FreeBSD before 11.2-RELEASE, multiple issues with the implementation of the stack guard-page reduce the protections afforded by the guard-page. This results in the possibility a poorly written process could be cause a stack overflow.
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Analysis
by VulDB Data Team • 07/08/2024
The vulnerability identified as CVE-2017-1084 affects FreeBSD operating systems prior to version 11.2-RELEASE, specifically targeting the implementation of stack guard-pages within the kernel's memory management subsystem. This flaw represents a critical weakness in the system's stack protection mechanisms that undermines fundamental security controls designed to prevent stack-based buffer overflow exploits. The stack guard-page serves as a critical defensive barrier that should prevent unauthorized code execution when stack corruption occurs, but the implementation defect allows for potential bypass of these protections.
The technical flaw stems from improper handling of guard-page mechanisms during stack allocation and management operations. When processes are created or when stack space is dynamically allocated, the kernel fails to properly enforce the guard-page boundaries that should separate the stack from adjacent memory regions. This vulnerability manifests through multiple implementation issues that collectively weaken the stack protection model, allowing malicious code or poorly written applications to potentially overwrite stack contents without triggering the expected protection mechanisms. The vulnerability operates at the kernel level and affects the core memory management functions that govern how stack memory is allocated and protected.
The operational impact of this vulnerability extends beyond simple stack corruption scenarios to encompass broader exploitation possibilities that could allow attackers to execute arbitrary code with elevated privileges. When a process experiences stack overflow conditions, the reduced guard-page protections mean that attackers can more easily overwrite return addresses, function pointers, or other critical stack data structures without triggering the expected memory protection violations. This weakness creates opportunities for exploitation through buffer overflow attacks, format string vulnerabilities, and other stack-based attack vectors that rely on predictable memory layout behaviors. The vulnerability particularly affects systems running older FreeBSD versions where the stack protection mechanisms have not been properly updated to address known implementation flaws.
This vulnerability aligns with CWE-129, which addresses improper handling of buffer boundaries and memory protection mechanisms, and relates to ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities. The weakness demonstrates how seemingly minor implementation details in memory management can have significant security implications, particularly when they affect fundamental protection mechanisms that are supposed to prevent code execution in unauthorized contexts. Organizations running FreeBSD systems prior to 11.2-RELEASE should prioritize immediate patching to address this vulnerability and restore proper stack protection mechanisms. The recommended mitigation strategy involves upgrading to FreeBSD 11.2-RELEASE or later versions where the stack guard-page implementation has been corrected to properly enforce memory boundaries and maintain the intended security protections against stack-based exploits.