CVE-2001-0734 in NetBSD
Summary
by MITRE
Hitachi Super-H architecture in NetBSD 1.5 and 1.4.1 allows a local user to gain privileges via modified Status Register contents, which are not properly handled by (1) the sigreturn system call or (2) the process_write_regs kernel routine.
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Analysis
by VulDB Data Team • 05/01/2019
The vulnerability described in CVE-2001-0734 represents a critical privilege escalation flaw within the Hitachi Super-H architecture implementation in NetBSD versions 1.5 and 1.4.1. This issue stems from improper handling of Status Register contents during critical kernel operations, specifically affecting the sigreturn system call and the process_write_regs kernel routine. The vulnerability operates at the kernel level, where the operating system fails to properly validate or sanitize the Status Register state when transitioning between user and kernel modes, creating an exploitable condition that allows local attackers to elevate their privileges.
The technical flaw manifests through the improper validation of processor status register contents during system call execution and process management operations. When a process executes a sigreturn system call or when kernel routines attempt to write register states through process_write_regs, the system does not adequately verify that the Status Register contents are valid or appropriate for the current execution context. This oversight enables a local attacker to manipulate the Status Register to include privileged bits or flags that should normally be restricted to kernel mode, effectively bypassing the kernel's privilege separation mechanisms. The vulnerability is classified under CWE-284 Access Control, specifically addressing inadequate privilege management in kernel space operations.
The operational impact of this vulnerability is significant as it allows a local user to gain elevated privileges without requiring authentication or special access rights. An attacker exploiting this flaw can execute arbitrary code with kernel-level privileges, potentially leading to complete system compromise. The attack vector requires local access to the system, but the consequences are severe as it undermines the fundamental security model of the operating system. The vulnerability affects systems running NetBSD 1.5 and 1.4.1 versions on Hitachi Super-H architecture platforms, which were commonly used in embedded systems and specialized computing environments where such privilege escalation could be particularly damaging.
Mitigation strategies for this vulnerability include immediate patching of the affected NetBSD versions to address the improper Status Register handling in kernel routines. System administrators should upgrade to patched versions of NetBSD that properly validate Status Register contents during sigreturn operations and process register management. Additionally, implementing kernel security modules or enhanced privilege separation mechanisms can provide additional defense layers. The vulnerability aligns with ATT&CK technique T1068 Privilege Escalation through kernel exploits, where adversaries leverage weaknesses in kernel operations to gain elevated system privileges. Organizations should also consider implementing runtime monitoring to detect anomalous Status Register modifications and establish proper access controls to limit local user capabilities in systems where such vulnerabilities may exist.