CVE-2018-4321

Vulnerability

CVE-2018-4321 is a validation issue in the entitlement verification mechanism on Apple platforms. The bug allows a local application to bypass entitlement checks, enabling it to access sensitive persistent account identifiers. Affected versions are iOS prior to 12, macOS Mojave prior to 10.14, and tvOS prior to 12 [1][2][3].

Exploitation

An attacker needs the ability to run a malicious app locally on the device. No additional authentication or user interaction beyond installing the app is required. The app can exploit the flawed entitlement verification to read persistent account identifiers without proper authorization.

Impact

Successful exploitation leads to disclosure of a persistent account identifier (such as an Apple ID-related token or identifier). This is an information disclosure that violates the confidentiality of the user's account identity, potentially enabling further attacks or identity tracking. The attacker gains no code execution or privilege escalation beyond reading this specific identifier.

Mitigation

Apple addressed the issue by releasing iOS 12 [1], macOS Mojave 10.14 [2], and tvOS 12 [3] on September 17-24, 2018. Users should update their devices to the latest software versions. No workaround exists for unpatched systems.