CVE-2011-3440 in iOS
Summary
by MITRE
The Passcode Lock feature in Apple iOS before 5.0.1 on the iPad 2 does not properly implement the locked state, which allows physically proximate attackers to access data by opening a Smart Cover during power-off confirmation.
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Analysis
by VulDB Data Team • 11/26/2021
The vulnerability described in CVE-2011-3440 represents a critical security flaw in Apple iOS versions prior to 5.0.1, specifically affecting the iPad 2 device model. This weakness resides within the Passcode Lock feature implementation, which is designed to protect user data through authentication mechanisms. The flaw demonstrates a fundamental failure in the device's security architecture where the lock state is not properly enforced during specific power management scenarios. The vulnerability exploits a physical proximity attack vector where an attacker with close access to the device can bypass the intended security measures by manipulating the Smart Cover mechanism during the device shutdown process.
The technical implementation flaw stems from improper state management within the iOS operating system's power management subsystem. When a user initiates a power-off sequence, the system should maintain a secure locked state until the shutdown process is complete. However, the iPad 2's Passcode Lock feature fails to properly maintain this secure state when the Smart Cover is opened during the power-off confirmation dialog. This creates a window of opportunity where the device's security mechanisms can be circumvented without proper authentication. The vulnerability specifically targets the interaction between the hardware sensor that detects Smart Cover opening and the software state management that should prevent unauthorized access during shutdown procedures.
The operational impact of this vulnerability is significant for users who rely on iOS devices for sensitive data protection. An attacker with physical proximity to a locked iPad 2 can potentially access all device contents, including personal information, emails, documents, and applications without proper authentication. This represents a direct violation of the principle of least privilege and undermines the fundamental security model that users expect from mobile operating systems. The attack requires minimal technical skill and can be executed in public or private environments where an attacker has brief physical access to the device. The vulnerability essentially creates a backdoor that allows immediate access to device data during a critical security transition period, making it particularly dangerous for enterprise users and individuals handling confidential information.
This vulnerability aligns with CWE-284, which describes improper access control in software systems, and demonstrates how physical security mechanisms can be bypassed through flawed software implementation. The attack pattern corresponds to techniques found in the ATT&CK framework under credential access and privilege escalation categories, where adversaries exploit system weaknesses to gain unauthorized access without traditional authentication methods. The flaw also relates to CWE-312, which addresses the exposure of sensitive data through improper implementation of security features. Organizations and individuals should consider this vulnerability when assessing their mobile device security posture, particularly in environments where physical access controls are inadequate. The recommended mitigation involves upgrading to iOS 5.0.1 or later versions where Apple has implemented proper state management for the power-off sequence, ensuring that the device maintains its locked state throughout the shutdown process regardless of Smart Cover interactions. Additionally, users should be educated about the risks of leaving devices unattended and the importance of maintaining current security updates to protect against known vulnerabilities.