CVE-2008-1595 in AIX
Summary
by MITRE
The proc filesystem in the kernel in IBM AIX 5.2 and 5.3 does not properly enforce directory permissions when a file executing from a directory has weaker permissions than the directory itself, which allows local users to obtain sensitive information.
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Analysis
by VulDB Data Team • 08/15/2019
The vulnerability identified as CVE-2008-1595 resides within the kernel implementation of IBM AIX operating systems version 5.2 and 5.3, specifically affecting the proc filesystem implementation. This issue represents a classic privilege escalation and information disclosure flaw that exploits the inconsistent handling of directory permissions within the kernel's file system access control mechanisms. The proc filesystem serves as a virtual file system that provides an interface to kernel data structures and process information, making it a critical component for system monitoring and administration functions. When a file executes from a directory where the file permissions are more restrictive than the parent directory, the kernel fails to properly enforce the directory's permission settings, creating an unexpected access path that violates fundamental security principles.
The technical flaw manifests in the kernel's permission checking logic where it fails to validate that executing files maintain consistent permission levels with their parent directories during access operations. This misconfiguration allows local users to traverse the filesystem hierarchy in unexpected ways, potentially accessing sensitive information that should be restricted by directory permissions. The vulnerability specifically impacts the interaction between file execution contexts and directory permission enforcement, where the kernel's security model breaks down when processing files that execute from directories with more permissive access controls than the files themselves. This creates a scenario where users can bypass normal access controls and potentially read or manipulate data that should remain protected by the directory's permission settings.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable local users to escalate privileges and access sensitive system resources. Attackers can leverage this flaw to gather information about running processes, system configurations, and potentially sensitive data stored in directories with weaker permissions. The vulnerability affects the integrity of the system's access control mechanisms and undermines the principle of least privilege that forms the foundation of secure system design. From a security perspective, this weakness represents a failure in the kernel's mandatory access control implementation and can be exploited to gain unauthorized access to system resources that should remain protected. The vulnerability is particularly concerning because it operates at the kernel level and affects core system functionality without requiring elevated privileges to exploit.
Mitigation strategies for this vulnerability should focus on applying the appropriate security patches provided by IBM for AIX 5.2 and 5.3 systems. Organizations should implement comprehensive system hardening measures including regular security updates, proper permission management for system directories, and monitoring of unusual access patterns in the proc filesystem. The vulnerability aligns with CWE-276, which describes improper permissions for critical resources, and can be mapped to ATT&CK techniques related to privilege escalation and credential access. System administrators should also consider implementing additional monitoring controls to detect potential exploitation attempts and ensure that directory permissions are properly enforced throughout the system. Given the nature of the vulnerability, it is essential to maintain proper system patch management procedures and regularly audit system configurations to prevent unauthorized access to sensitive information.