CVE-2016-4593 in iOS
Summary
by MITRE
The Siri Contacts component in Apple iOS before 9.3.3 allows physically proximate attackers to read arbitrary Contact card information via unspecified vectors.
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Analysis
by VulDB Data Team • 09/05/2022
The vulnerability identified as CVE-2016-4593 represents a critical security flaw in Apple iOS versions prior to 9.3.3, specifically affecting the Siri Contacts component. This vulnerability exposes sensitive personal information through a method that requires only physical proximity to the affected device, making it particularly concerning for users who may not be aware of the attack vector. The flaw exists within the Siri functionality that processes voice commands related to contacts, creating an unexpected pathway for unauthorized information disclosure. Security researchers have classified this issue as a privilege escalation vulnerability that allows attackers to bypass normal access controls and retrieve contact information without proper authentication.
The technical implementation of this vulnerability stems from insufficient input validation and access control mechanisms within the Siri Contacts subsystem. Attackers exploiting this flaw can leverage voice commands to access contact information from the device's address book without requiring passcode entry or biometric authentication. The unspecified vectors mentioned in the description suggest that the vulnerability may manifest through multiple attack paths including voice recognition manipulation, command injection, or improper session handling within the Siri interface. This vulnerability operates at the application layer and specifically targets the iOS Contacts framework, which stores sensitive personal data including names, phone numbers, email addresses, and other contact details that could be used for social engineering attacks or identity theft.
The operational impact of CVE-2016-4593 extends beyond simple information disclosure, as it creates opportunities for more sophisticated attacks such as targeted phishing campaigns, identity fraud, and corporate espionage. The physical proximity requirement does not limit the attack surface significantly since attackers can approach unsuspecting users in public spaces, workplaces, or other environments where personal devices are commonly left unattended. This vulnerability particularly affects enterprise environments where employees may be targeted for information gathering, as contact information can reveal organizational structures, communication patterns, and potential targets for further attacks. The vulnerability operates at the system level and can be exploited by attackers with minimal technical expertise, making it a significant concern for both individual users and organizations.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-200 (Information Exposure) and CWE-284 (Improper Access Control) classifications, demonstrating how insufficient access controls can lead to unauthorized data access. The ATT&CK framework categorizes this under T1566 (Phishing) and T1005 (Data from Local System) as attackers can leverage this vulnerability to gather information for more complex attacks. Organizations should implement immediate mitigations including prompt OS updates to iOS 9.3.3 or later versions, along with user education about the risks of leaving devices unattended in public spaces. Additional protective measures include enabling strong passcode requirements, configuring automatic screen lock timeouts, and implementing mobile device management policies that enforce security updates. The vulnerability serves as a reminder of the importance of securing voice-activated interfaces and highlights the need for comprehensive security testing of all application components, particularly those that interact with sensitive user data through non-traditional access methods.