CVE-2017-7144 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11 is affected. Safari before 11 is affected. The issue involves the "WebKit" component. It allows remote attackers to track Safari Private Browsing users by leveraging cookie mishandling.
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Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-7144 represents a significant privacy flaw in Apple's WebKit rendering engine that affected iOS versions prior to 11 and Safari versions before 11. This security issue stems from improper cookie handling mechanisms within the WebKit component that enables malicious actors to track users who believe they are browsing privately through Safari's private browsing mode. The flaw specifically exploits the way WebKit manages cookies and other tracking mechanisms during private browsing sessions, creating a persistent tracking capability that undermines the fundamental privacy protections users expect from private browsing modes.
The technical implementation of this vulnerability occurs through WebKit's cookie management system where the component fails to properly isolate cookies between regular and private browsing contexts. When users engage in private browsing, the WebKit engine should maintain strict separation between tracking data and private session data to prevent cross-context tracking. However, this flaw allows attackers to inject or manipulate cookie data in a way that persists across browsing sessions, enabling them to correlate user activities and maintain tracking capabilities even when private browsing mode is active. This behavior violates the core principle of private browsing that should prevent websites from storing persistent identifiers that could be used for user tracking.
The operational impact of CVE-2017-7144 extends beyond simple privacy concerns to potentially enable sophisticated tracking campaigns that could compromise user anonymity and personal data. Attackers can leverage this vulnerability to create persistent identifiers that track user behavior across different websites and sessions, effectively nullifying the privacy protections that private browsing modes are designed to provide. The vulnerability affects a wide range of Apple devices including iPhones, iPads, and Mac computers running affected versions of iOS and Safari, making it a significant concern for users who rely on private browsing for sensitive activities. This flaw particularly impacts users who engage in confidential research, sensitive communications, or activities where maintaining anonymity is crucial.
From a cybersecurity perspective, this vulnerability aligns with CWE-200, which addresses "Information Exposure" and CWE-355, which covers "Security Weaknesses in Web Applications." The issue also maps to ATT&CK technique T1566, "Phishing", as attackers could use this vulnerability to enhance their tracking capabilities during phishing campaigns or other social engineering attacks. The vulnerability demonstrates how seemingly minor implementation flaws in core components like WebKit can create significant security gaps that undermine user trust and privacy expectations. Organizations and individuals should consider this vulnerability as part of broader privacy protection strategies, particularly when evaluating the effectiveness of browser-based privacy controls and the need for additional protective measures beyond standard browser security features.
The remediation for this vulnerability requires updating to iOS 11 or later versions and Safari 11 or later, which include patches that properly isolate cookie handling between regular and private browsing contexts. Apple's security updates address the root cause by implementing stricter cookie management protocols within WebKit that prevent cross-context cookie manipulation. Users should also consider additional privacy protection measures such as using privacy-focused browsers, employing browser extensions that block tracking scripts, and maintaining awareness of privacy settings across all installed applications. Security professionals should monitor for similar vulnerabilities in other browser components and ensure comprehensive testing of privacy features during security assessments. The vulnerability serves as a reminder of the critical importance of proper isolation mechanisms in privacy-sensitive components and the need for continuous security validation of core browser functionalities.