CVE-2016-1849 in Safari
Summary
by MITRE
The "Clear History and Website Data" feature in Apple Safari before 9.1.1, as used in iOS before 9.3.2 and other products, mishandles the deletion of browsing history, which might allow local users to obtain sensitive information by leveraging read access to a Safari directory.
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Analysis
by VulDB Data Team • 08/21/2022
The vulnerability identified as CVE-2016-1849 resides within Apple Safari's "Clear History and Website Data" functionality, representing a critical information disclosure flaw that persisted across multiple versions of iOS and Safari. This vulnerability specifically affects Safari versions prior to 9.1.1 and iOS versions prior to 9.3.2, indicating a prolonged window of exposure that allowed attackers to exploit the improper handling of browsing history deletion processes. The flaw manifests when the browser attempts to clear user data, creating a scenario where sensitive information remains accessible to local users who possess read access to the Safari directory structure.
The technical implementation of this vulnerability stems from inadequate sanitization of data during the clearing process, where the system fails to properly remove all traces of browsing history and website data from persistent storage. When users initiate the "Clear History and Website Data" command, the underlying mechanism does not completely purge cached information, cookies, or temporary files from the filesystem, leaving residual data that can be accessed through direct file system operations. This improper handling creates a persistent information leakage channel that bypasses the intended security controls designed to protect user privacy and sensitive browsing information.
From an operational perspective, this vulnerability presents a significant risk to user privacy and data protection, as local attackers with read access to the Safari directory can potentially recover deleted browsing history, cached web content, and other sensitive information that should have been permanently removed. The impact extends beyond simple privacy concerns to encompass potential exploitation for targeted attacks, credential harvesting, and forensic analysis of user activities. Security researchers have categorized this vulnerability under CWE-200, which addresses "Information Exposure," while threat actors leveraging this flaw would typically follow ATT&CK technique T1074.001 for data staging and T1082 for system information discovery to maximize the exploitation potential.
The mitigation strategy for CVE-2016-1849 involves immediate deployment of Apple's security patches and updates, specifically iOS 9.3.2 and Safari 9.1.1, which address the improper directory handling during data deletion processes. Organizations should implement comprehensive patch management protocols to ensure all affected systems receive updates promptly, while security teams should monitor for any attempts to exploit this vulnerability in the wild. Additionally, system administrators should conduct regular security assessments of Safari configurations and consider implementing additional access controls to limit read permissions on sensitive browser directories, thereby reducing the attack surface available to local users who might attempt to leverage this information disclosure flaw for unauthorized data access.