CVE-2008-0055 in Mac OS X
Summary
by MITRE
Foundation in Apple Mac OS X 10.4.11 creates world-writable directories while NSFileManager copies files recursively and only modifies the permissions afterward, which allows local users to modify copied files to cause a denial of service and possibly gain privileges.
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Analysis
by VulDB Data Team • 08/07/2019
The vulnerability described in CVE-2008-0055 represents a critical flaw in the Foundation framework of Apple Mac OS X 10.4.11 where the NSFileManager class exhibits improper privilege handling during recursive file copying operations. This issue stems from the implementation approach where the system first creates world-writable directories before modifying their permissions, creating a window of opportunity for malicious local users to exploit the temporal gap between directory creation and permission setting. The flaw specifically affects the recursive copying functionality that is commonly used throughout the operating system and applications, making it a widespread potential attack vector. This vulnerability is categorized under CWE-276, which addresses improper permissions and access control issues, and aligns with ATT&CK technique T1068, which covers local privilege escalation through improper file permissions. The fundamental technical issue occurs because the system creates directories with overly permissive settings of 0777 (read, write, execute for all users) during the initial phase of file copying, before subsequently applying more restrictive permissions. This creates a race condition where an attacker can manipulate files within these temporarily permissive directories before the system corrects the permissions, potentially allowing them to inject malicious code or modify critical system files. The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can enable privilege escalation attacks when the copied files are subsequently executed with elevated privileges. Local users with minimal access can exploit this weakness to gain unauthorized access to system resources, compromise system integrity, and potentially establish persistent access to the affected system. The vulnerability affects the core file management operations that are fundamental to the operating system's functionality, making it particularly dangerous as it can be leveraged through any application or system process that utilizes the NSFileManager recursive copy functionality. This flaw is especially concerning in multi-user environments where local users may not have administrative privileges but could still exploit this weakness to compromise system security. The vulnerability demonstrates a classic improper privilege handling pattern that violates security best practices, as it fails to maintain proper access controls throughout the entire file operation lifecycle. Organizations and system administrators should prioritize patching this vulnerability as it represents a significant risk to system integrity and security posture, particularly in environments where multiple users have local access to affected systems. The remediation involves updating to a patched version of Mac OS X that properly implements permission handling during recursive file copying operations, ensuring that directory permissions are correctly set from the initial creation phase rather than modifying them afterward. This vulnerability highlights the importance of proper privilege management in system frameworks and underscores the need for comprehensive security testing of core operating system components that handle file operations and access controls. The attack surface for this vulnerability is extensive, as it can be triggered through any application or system process that utilizes the affected NSFileManager functionality, making it a critical security concern for all Mac OS X 10.4.11 systems.