CVE-2001-0624 in QNX
Summary
by MITRE
QNX 2.4 allows a local user to read arbitrary files by directly accessing the mount point for the FAT disk partition, e.g. /fs-dos.
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Analysis
by VulDB Data Team • 05/31/2018
The vulnerability described in CVE-2001-0624 represents a critical access control flaw in QNX 2.4 operating system that enables local users to bypass normal file system permissions and access arbitrary files through direct mount point manipulation. This issue stems from inadequate privilege checking mechanisms within the QNX file system implementation, specifically affecting the FAT file system driver that handles disk partition mounting operations. The vulnerability is classified as a local privilege escalation vector since it allows attackers who already have access to the system to gain unauthorized access to files they should not be able to read.
The technical flaw manifests through the improper handling of mount points for FAT disk partitions in QNX 2.4 systems. When a FAT partition is mounted, the system creates a mount point such as /fs-dos that provides direct access to the underlying file system structure. The vulnerability occurs because the system does not properly validate access permissions when users directly access these mount points, allowing them to traverse file system boundaries and read files that are normally protected by standard access controls. This flaw operates at the kernel level file system driver, making it particularly dangerous as it bypasses user-space security mechanisms.
The operational impact of this vulnerability is significant for any organization using QNX 2.4 systems, particularly in embedded environments where such systems are commonly deployed. Attackers can exploit this vulnerability to access sensitive data including configuration files, user credentials, system logs, and other confidential information stored on FAT partitions. The vulnerability is especially concerning in industrial control systems, automotive applications, and other embedded devices where QNX 2.4 was historically used. From an attacker's perspective, this represents a low-effort privilege escalation technique that can be automated and does not require special tools or complex exploitation methods.
This vulnerability aligns with CWE-264, which addresses permissions, privileges, and access controls in software systems, and demonstrates the critical importance of proper access control implementation at all levels of the operating system. The issue also relates to ATT&CK technique T1068, which covers local privilege escalation through kernel exploits, although this particular case operates through file system manipulation rather than kernel code execution. Organizations should implement immediate mitigations including restricting direct access to mount points, implementing proper file system permissions, and ensuring that only authorized users have access to system-level file operations. The vulnerability underscores the need for comprehensive security testing of embedded operating systems and highlights the importance of proper privilege separation in system design. System administrators should also consider implementing monitoring solutions that can detect unauthorized access attempts to mount points and file system structures to provide early warning of potential exploitation attempts.