CVE-2017-7146 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11 is affected. The issue involves the "Security" component. It allows attackers to track users across installs via a crafted app that leverages Keychain data mishandling.
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Analysis
by VulDB Data Team • 01/19/2021
The vulnerability identified as CVE-2017-7146 represents a significant security flaw within Apple's iOS operating system affecting versions prior to iOS 11. This weakness resides within the Security component and demonstrates how improper handling of Keychain data can be exploited to track users across different application installations. The vulnerability stems from the manner in which iOS manages cryptographic key storage and retrieval, creating an avenue for persistent tracking mechanisms that bypass typical privacy protections.
The technical implementation of this vulnerability exploits the Keychain Services API within iOS, where applications can store and retrieve cryptographic keys and credentials. Attackers can craft malicious applications that manipulate Keychain data to establish persistent identifiers that persist across app installations and device resets. This occurs because the system fails to properly isolate Keychain items between different applications or maintain appropriate access controls that would prevent cross-application data leakage. The flaw operates at the system level where Keychain items are stored with insufficient separation, allowing malicious actors to access and leverage previously stored credentials or identifiers.
From an operational impact perspective, this vulnerability enables sophisticated tracking capabilities that undermine user privacy and security expectations. The persistent tracking mechanism allows attackers to maintain user identification across multiple installations and potentially across different devices, creating a comprehensive user profile that can be used for targeted advertising, surveillance, or more malicious purposes. This tracking capability extends beyond simple analytics to create persistent identifiers that can be used to correlate user behavior across different applications and services, violating fundamental privacy principles that users expect from mobile operating systems.
The vulnerability aligns with CWE-255 Credential Management Issues and represents a specific instance of improper key management within the iOS security architecture. It also maps to ATT&CK technique T1185, which involves the use of application installation for persistence and tracking. The flaw demonstrates how seemingly minor implementation details in cryptographic systems can create significant privacy vulnerabilities. Security researchers have noted that this issue particularly affects the integrity of the Keychain Services framework, where access controls and data isolation mechanisms fail to prevent unauthorized cross-application data access.
Mitigation strategies for this vulnerability require immediate system updates to iOS 11 or later versions where Apple has implemented proper Keychain isolation mechanisms. Organizations should also implement application whitelisting and monitoring for suspicious Keychain access patterns. Network-level monitoring can help detect unusual Keychain data access behaviors that may indicate exploitation attempts. Additionally, users should maintain regular system updates and exercise caution when installing applications that request excessive permissions or demonstrate unusual Keychain access patterns. The fix implemented by Apple addresses the root cause by strengthening Keychain item access controls and ensuring proper isolation between different applications' stored credentials and identifiers.