CVE-2014-1351 in iOS
Summary
by MITRE
Siri in Apple iOS before 7.1.2 allows physically proximate attackers to bypass an intended lock-screen passcode requirement, and read a contact list, via a Siri request that refers to a contact ambiguously.
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Analysis
by VulDB Data Team • 06/01/2017
This vulnerability resides in the Siri voice recognition system of Apple iOS versions prior to 7.1.2, representing a significant security flaw that undermines the device's fundamental lock-screen protection mechanisms. The vulnerability operates through a sophisticated bypass technique that exploits the ambiguity handling capabilities of Siri's natural language processing system. Attackers can exploit this weakness by issuing carefully crafted voice commands that reference contacts in ambiguous ways, effectively circumventing the passcode requirement that should normally be enforced when accessing device data from the lock screen. This represents a critical failure in the device's access control architecture, where the security boundary between authenticated and unauthenticated access states becomes effectively porous.
The technical implementation of this vulnerability stems from how Siri processes ambiguous contact references within the context of lock-screen interactions. When a user issues a voice command such as "Call mom" or "Send message to John" while the device is locked, the system's contact resolution mechanism fails to properly verify authentication status before executing the command. This flaw manifests specifically in the way Siri handles partial or ambiguous contact names, where the system's attempt to disambiguate the reference does not properly validate the user's authorization level. The vulnerability is particularly insidious because it requires only physical proximity to the device, eliminating the need for sophisticated social engineering or advanced technical exploitation techniques. This aligns with the common attack pattern described in the attack tree framework where physical access combined with minimal technical knowledge can result in significant information disclosure.
The operational impact of this vulnerability extends far beyond simple contact list access, as it demonstrates a fundamental flaw in the device's security model that could potentially be extended to access other protected data types. An attacker with physical access to an iOS device could potentially extract sensitive information including contact details, call logs, messages, and potentially other personal data stored on the device. The vulnerability's exploitation does not require network connectivity or specialized tools, making it particularly dangerous in environments where devices may be left unattended or where physical security controls are inadequate. This type of vulnerability is classified under the Common Weakness Enumeration category of insufficient verification of data authenticity, specifically relating to authentication bypass mechanisms. The attack vector aligns with the attack technique described in the MITRE ATT&CK framework under credential access and privilege escalation, where an attacker exploits application-level weaknesses to gain unauthorized access to protected resources.
The security implications of this vulnerability highlight the challenges in implementing secure voice recognition systems within mobile environments where user convenience must balance against security requirements. Apple's implementation failed to properly enforce authentication boundaries when processing voice commands, creating a pathway for unauthorized access that bypasses the expected security controls. The vulnerability's discovery and subsequent patching in iOS 7.1.2 demonstrates the importance of proper input validation and authentication checking in mobile operating systems. Organizations and individuals should ensure that all iOS devices are updated to versions that include the necessary security patches, as this vulnerability represents a clear example of how seemingly minor implementation flaws can create significant security risks. The remediation approach taken by Apple involved strengthening the authentication verification process for voice commands and ensuring that all contact-related operations require proper passcode verification regardless of the command's complexity or the ambiguity of the requested contact information. This vulnerability serves as a reminder of the critical importance of comprehensive security testing, particularly for features that operate in high-risk contexts such as lock-screen interactions where user trust and security are paramount.