CVE-2016-1772 in Safari
Summary
by MITRE
The Top Sites feature in Apple Safari before 9.1 mishandles cookie storage, which makes it easier for remote web servers to track users via unspecified vectors.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2016-1772 resides within Apple Safari's Top Sites feature, representing a significant privacy concern that undermines user tracking protection mechanisms. This flaw specifically affects Safari versions prior to 9.1, where the browser's handling of cookie storage during Top Sites operations creates exploitable conditions for remote attackers. The vulnerability operates through unspecified vectors that allow malicious web servers to establish persistent tracking mechanisms, effectively bypassing intended privacy safeguards that should isolate user browsing data from external tracking entities.
The technical implementation of this vulnerability stems from improper cookie management within Safari's Top Sites functionality, which serves as a quick access feature displaying frequently visited websites. When users interact with this feature, the browser's cookie handling mechanism fails to properly isolate tracking cookies from legitimate session data, creating opportunities for cross-site tracking. This mismanagement allows remote servers to store cookies that persist beyond typical session boundaries, enabling them to maintain user identification across different browsing sessions and potentially across multiple domains. The flaw essentially creates a persistent tracking channel that operates independently of standard privacy controls.
The operational impact of CVE-2016-1772 extends beyond simple user tracking, as it fundamentally compromises the privacy assurances that users expect from modern web browsers. Attackers can leverage this vulnerability to build comprehensive user profiles by correlating browsing behavior across multiple sites, effectively creating persistent identifiers that bypass traditional privacy mechanisms. This vulnerability particularly affects users who rely on Safari's Top Sites feature, as the tracking occurs during normal browsing operations without explicit user awareness or consent. The implications include potential exposure of personal browsing habits, demographic targeting, and behavioral analytics that could be exploited for malicious purposes.
Mitigation strategies for this vulnerability require immediate patching of Safari to version 9.1 or later, which addresses the underlying cookie handling mechanisms within the Top Sites feature. System administrators should also implement browser security policies that disable or restrict Top Sites functionality where possible, particularly in enterprise environments where privacy controls are paramount. Users should be educated about the risks associated with enabling features that may compromise privacy, and security monitoring should include detection of unusual cookie behavior patterns that might indicate tracking activity. This vulnerability aligns with CWE-200, which addresses improper information handling, and represents a specific instance of information exposure through inadequate cookie management practices that violates user privacy expectations.
The broader implications of this vulnerability highlight the critical importance of proper cookie isolation mechanisms in web browsers, particularly for features that maintain persistent user data. Security professionals should recognize this as a precursor to more sophisticated tracking techniques that could exploit similar cookie handling flaws across different browser implementations. Organizations implementing security controls should consider this vulnerability when assessing browser security configurations and user privacy protection measures, as it demonstrates how seemingly benign features can become attack vectors when proper isolation mechanisms are not implemented. The vulnerability also underscores the need for comprehensive privacy controls that address not just network-level tracking but also client-side feature implementations that may inadvertently compromise user anonymity.