CVE-2017-1000374 in NetBSD
Summary
by MITRE
A flaw exists in NetBSD's implementation of the stack guard page that allows attackers to bypass it resulting in arbitrary code execution using certain setuid binaries. This affects NetBSD 7.1 and possibly earlier versions.
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Analysis
by VulDB Data Team • 12/29/2020
The vulnerability identified as CVE-2017-1000374 represents a critical stack protection mechanism failure within NetBSD operating systems. This flaw specifically targets the implementation of stack guard pages, which are essential memory protection features designed to detect and prevent stack-based buffer overflow attacks. The stack guard page serves as a sentinel region of memory that triggers a segmentation fault when accessed, thereby preventing attackers from overwriting return addresses or other critical stack data structures. When this protection mechanism is compromised, it creates a pathway for malicious actors to execute arbitrary code with elevated privileges.
The technical implementation flaw lies in how NetBSD handles the stack guard page mechanism, particularly when processing certain setuid binaries. Setuid binaries execute with the privileges of the file owner rather than the user who invoked them, making them prime targets for exploitation. The vulnerability occurs because the operating system's memory management routines fail to properly enforce the guard page boundaries, allowing attackers to manipulate memory layout in ways that bypass the intended protection. This issue affects NetBSD version 7.1 and potentially earlier releases, indicating a long-standing problem in the kernel's memory management subsystem.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to leverage existing setuid binaries as attack vectors. When an attacker successfully bypasses the stack guard page protection, they can inject malicious code into memory spaces that would normally be protected, potentially leading to full system compromise. This vulnerability is particularly dangerous because it operates at the kernel level, where memory protection mechanisms are supposed to be most robust. The flaw essentially undermines fundamental security assumptions about how memory should be protected, making it easier for attackers to perform sophisticated exploitation techniques that would otherwise be blocked by standard stack protection mechanisms.
Mitigation strategies for CVE-2017-1000374 should focus on immediate system updates to patched NetBSD versions that address the stack guard page implementation. Organizations should also implement comprehensive monitoring of setuid binary execution and memory access patterns that could indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and relates to ATT&CK technique T1068, which involves local privilege escalation through exploitation of system vulnerabilities. Security teams should conduct thorough inventory assessments to identify all setuid binaries on affected systems and implement additional controls such as mandatory access controls or extended protection mechanisms to reduce the attack surface. Additionally, regular security audits of memory management implementations should be performed to identify similar vulnerabilities in other system components.