CVE-2016-4698 in macOS
Summary
by MITRE
AppleMobileFileIntegrity in Apple iOS before 10 and OS X before 10.12 mishandles process entitlement and Team ID values in the task port inheritance policy, which allows attackers to execute arbitrary code in a privileged context via a crafted app.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-4698 resides within AppleMobileFileIntegrity, a critical component of Apple's security architecture that governs file integrity and process execution policies on iOS and macOS systems. This flaw specifically impacts versions prior to iOS 10 and OS X 10.12, creating a significant security weakness in the operating system's privilege management mechanisms. The vulnerability stems from improper handling of process entitlements and Team ID values during task port inheritance operations, which are fundamental components of Apple's code signing and sandboxing architecture.
The technical flaw manifests in the manner how AppleMobileFileIntegrity processes and validates entitlements when inheriting task ports from parent processes. When applications attempt to inherit task ports from privileged contexts, the system fails to properly validate the Team ID associated with the requesting process against the entitlements of the parent process. This oversight creates a privilege escalation vector where malicious applications can manipulate the inheritance policy to gain elevated privileges. The vulnerability is classified under CWE-269 as "Improper Privilege Management" and aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" through improper access control mechanisms.
The operational impact of this vulnerability is severe as it allows attackers to execute arbitrary code within a privileged context without requiring user interaction or physical access to the device. An attacker could craft a malicious application that, when installed and executed, would leverage this flaw to bypass system security controls and gain root-level access to the device. This capability enables full system compromise including access to sensitive user data, installation of additional malware, and potential lateral movement within network environments where the compromised device exists. The vulnerability essentially undermines the core security model of iOS and macOS by allowing unauthorized privilege escalation through legitimate system interfaces.
Mitigation strategies for CVE-2016-4698 require immediate system updates to iOS 10 or macOS 10.12 and later versions where Apple has implemented proper validation of entitlements and Team ID values during task port inheritance. Organizations should also implement strict application whitelisting policies and monitor for unauthorized application installations on affected systems. Security administrators should conduct thorough vulnerability assessments to identify any systems running vulnerable versions and ensure timely patch deployment. The fix addresses the underlying issue by strengthening the validation process for entitlements and Team IDs during task port inheritance, preventing malicious applications from exploiting the privilege escalation pathway. This vulnerability serves as a critical reminder of the importance of proper privilege management in operating system security architectures and the potential consequences of inadequate validation of system-level operations.