CVE-2014-4391 in Mac OS X
Summary
by MITRE
The Code Signing feature in Apple OS X before 10.10 does not properly handle incomplete resource envelopes in signed bundles, which allows remote attackers to bypass intended app-author restrictions by omitting an execution-related resource.
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Analysis
by VulDB Data Team • 02/23/2022
The vulnerability described in CVE-2014-4391 represents a critical code signing flaw within Apple's operating system that fundamentally undermines the security model designed to protect users from malicious software. This weakness exists in the code signing implementation of OS X versions prior to 10.10, where the system fails to properly validate the completeness of resource envelopes within signed application bundles. The issue stems from insufficient validation mechanisms that should ensure all required execution-related resources are present and properly structured within code-signed applications. Attackers can exploit this gap by creating malicious bundles that omit essential execution resources while maintaining valid signatures, effectively circumventing the intended security controls that restrict application execution based on authorship and integrity.
The technical flaw manifests in the improper handling of resource envelopes during code signature validation processes, specifically when the system encounters incomplete or missing resources within signed bundles. This vulnerability operates at the core of the operating system's security architecture by exploiting a gap in the validation logic that should enforce complete resource sets for legitimate applications. The weakness allows attackers to craft malicious applications that appear to be properly signed and authorized while actually containing only partial resource structures. This incomplete resource handling creates a scenario where the code signing verification process passes successfully even though the application bundle lacks critical execution components that would normally be required for proper functionality. The vulnerability is particularly dangerous because it operates at the system level where code signing is meant to provide the highest degree of trust and authorization control.
The operational impact of this vulnerability extends beyond simple bypass of code signing restrictions, creating a pathway for sophisticated attack vectors that can compromise user systems and data. Remote attackers can leverage this weakness to deploy malicious applications that appear legitimate to the operating system's security checks, potentially enabling them to execute unauthorized code with elevated privileges. The vulnerability affects the fundamental trust model of OS X applications, where users and system policies rely on code signing to verify application authenticity and prevent unauthorized modifications. This flaw essentially allows attackers to create applications that can bypass Gatekeeper protections and other security mechanisms that depend on proper code signing validation. The implications are particularly severe for enterprise environments where application control policies are enforced through code signing, as attackers can circumvent these controls without detection.
Mitigation strategies for CVE-2014-4391 require immediate system updates to OS X 10.10 or later versions where Apple has addressed the code signing validation issues. Organizations should implement comprehensive patch management procedures to ensure all systems receive the necessary security updates promptly. Additional defensive measures include enhanced monitoring of application execution patterns, implementation of application whitelisting policies, and regular security audits of code signing practices. The vulnerability aligns with CWE-254 in the Common Weakness Enumeration catalog, which identifies weaknesses in code signing validation and resource handling. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and defense evasion, as attackers can bypass security controls while maintaining operational stealth. System administrators should also consider implementing additional security layers such as extended protection mechanisms and behavioral monitoring to detect anomalous application execution patterns that might indicate exploitation attempts.