CVE-2018-4055 in Renderman
Summary
by MITRE
A local privilege escalation vulnerability exists in the install helper tool of the Mac OS X version of Pixar Renderman, version 22.2.0. A user with local access can use this vulnerability to read any root file from the file system. An attacker would need local access to the machine to successfully exploit this flaw.
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Analysis
by VulDB Data Team • 07/29/2023
The vulnerability identified as CVE-2018-4055 represents a critical local privilege escalation flaw within the Pixar Renderman software suite for macOS operating systems. This security weakness specifically affects version 22.2.0 of the Mac OS X implementation and stems from improper privilege handling within the install helper tool component. The vulnerability creates a dangerous condition where a malicious user with local system access can exploit this flaw to gain unauthorized read access to any file on the system that would typically require root privileges to access. This type of vulnerability falls under the category of privilege escalation attacks and directly violates the principle of least privilege that forms the foundation of secure system design.
The technical implementation of this vulnerability involves a flaw in the helper tool's permission model where it fails to properly validate file access requests or enforce appropriate access controls. When the install helper tool processes file operations, it does not adequately restrict the scope of files that can be accessed, allowing arbitrary file reads regardless of the file's permission settings or ownership. This represents a classic case of insufficient access control mechanisms and can be categorized under CWE-284 which addresses improper access control. The vulnerability essentially creates a backdoor through which local users can bypass normal file system protections and directly read root-owned files, potentially exposing sensitive system information, configuration files, or authentication data that should remain protected from unauthorized access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with a pathway to escalate their privileges and potentially gain deeper system control. An attacker who successfully exploits this vulnerability could access critical system files including configuration data, user credentials, or system logs that might reveal additional attack vectors or system weaknesses. This type of local privilege escalation vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation techniques. The attack requires only local system access, making it particularly dangerous in environments where multiple users share the same system or where physical access to machines cannot be fully controlled. The vulnerability essentially transforms a local user account into a root-level access point, providing a significant escalation in attack capabilities.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and system hardening measures. The primary solution involves upgrading to a patched version of Pixar Renderman that properly addresses the access control flaw in the install helper tool. System administrators should also implement additional security controls such as restricting local user access to system components, monitoring for unauthorized file access patterns, and ensuring proper privilege separation between user processes and system utilities. The vulnerability demonstrates the importance of proper privilege management in system tools and highlights the need for comprehensive security testing of all components within software installations, particularly those that require elevated privileges to function. Organizations should also consider implementing principle of least privilege practices for all system utilities and regularly audit installed software for similar security weaknesses that could provide unauthorized access to system resources.