CVE-2016-4781 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.2 is affected. The issue involves the "SpringBoard" component, which allows physically proximate attackers to bypass the passcode attempt counter and unlock a device via unspecified vectors.
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Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-4781 represents a significant security flaw within Apple's iOS operating system affecting versions prior to 10.2. This weakness resides within the SpringBoard component, which serves as the core user interface framework responsible for managing the home screen, lock screen, and passcode authentication mechanisms. The vulnerability specifically targets the passcode attempt counter functionality that is designed to prevent unauthorized access through repeated guessing attempts. The flaw enables attackers who are physically present near the device to circumvent the security measures that typically limit passcode entry attempts, effectively allowing them to unlock the device without proper authentication.
The technical nature of this vulnerability stems from insufficient validation mechanisms within the SpringBoard component that handles passcode verification. When a user enters an incorrect passcode, the system should increment a counter and potentially lock the device after a predetermined number of failed attempts. However, the flaw allows attackers to exploit timing or sequence-based vectors that bypass this counter mechanism entirely. This creates a scenario where an attacker can repeatedly attempt passcode entry without triggering the intended security protections, effectively neutralizing the passcode-based authentication system. The vulnerability's classification aligns with CWE-307, which addresses improper restriction of repeated operations, and demonstrates how inadequate session management can lead to authentication bypass scenarios.
The operational impact of CVE-2016-4781 extends beyond simple unauthorized access, as it represents a fundamental weakness in the device's security architecture that could enable various malicious activities. Physically proximate attackers can exploit this vulnerability to gain access to sensitive personal data, financial information, communication records, and other confidential content stored on the device. The attack vector's proximity requirement does not diminish its severity, as it can be exploited in various real-world scenarios including public transportation, offices, or any environment where an attacker might reasonably position themselves near a target device. This vulnerability significantly undermines the trust model that iOS relies on for device security and represents a critical failure in the system's ability to protect against determined attackers who can observe or interact with the device during normal use.
Organizations and individual users affected by this vulnerability should implement immediate mitigations including updating to iOS 10.2 or later versions where Apple has addressed the issue through patches to the SpringBoard component. Additionally, users should consider enabling additional security measures such as biometric authentication methods like Face ID or Touch ID, which provide alternative authentication mechanisms that are not affected by this specific vulnerability. Security professionals should monitor for exploitation attempts and implement network-based detection measures that can identify unusual passcode entry patterns that might indicate exploitation of this vulnerability. The remediation process should also include educating users about the importance of physical security, as this vulnerability specifically exploits situations where an attacker has physical access to the device, making user awareness and device positioning practices critical components of overall security posture.