CVE-2019-8620 in watchOS
Summary
by MITRE
A user privacy issue was addressed by removing the broadcast MAC address. This issue is fixed in iOS 12.3, tvOS 12.3, watchOS 5.2.1. A device may be passively tracked by its WiFi MAC address.
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Analysis
by VulDB Data Team • 09/19/2023
The vulnerability described in CVE-2019-8620 represents a significant privacy concern related to wireless device tracking mechanisms within Apple's mobile operating systems. This issue stems from the inherent characteristics of wifi networking protocols where devices broadcast their unique media access control addresses to identify themselves to nearby access points and network infrastructure. The flaw allowed for persistent tracking of user devices through these broadcast mac addresses, creating a potential privacy risk that could be exploited by malicious actors or tracking services to monitor user movements and behaviors across different locations and time periods.
The technical implementation of this vulnerability involves the improper handling of mac address broadcasting within the wifi stack of affected apple operating systems. When devices connect to wifi networks or operate in wifi scanning mode, they continuously broadcast their unique mac addresses to discover available networks and maintain connectivity. This broadcast mechanism, while necessary for standard network operations, created a persistent identifier that could be collected and correlated by third parties without user knowledge or consent. The vulnerability specifically affected the way these addresses were managed and presented during network communication, allowing for passive tracking of devices based on their unique hardware identifiers.
The operational impact of this vulnerability extends beyond simple privacy concerns to encompass broader security implications for user mobility and location tracking. Attackers or surveillance systems could potentially collect these broadcast mac addresses from multiple locations and use them to build profiles of user behavior patterns, frequented locations, and movement routines. This passive tracking capability represents a direct violation of user privacy expectations and could enable various malicious activities including targeted advertising, stalking, or more sophisticated surveillance operations. The vulnerability particularly affected users of ios 12.2 and earlier versions, tvos 12.2 and earlier, and watchos 5.2 and earlier, creating a window of exposure for users who had not yet updated their systems.
Apple addressed this vulnerability through a comprehensive fix implemented in ios 12.3, tvos 12.3, and watchos 5.2.1, which involved modifying the mac address broadcasting behavior to prevent the disclosure of unique identifiers during normal network operations. The solution aligns with industry best practices for privacy protection and follows the principle of least privilege by minimizing the information exposed during routine network activities. This fix specifically targets the broadcast mac address issue by implementing randomized or nullified mac address values during network scanning and connection processes, preventing the consistent identification of devices across different network environments.
The vulnerability demonstrates characteristics consistent with CWE-384, which addresses the exposure of sensitive information through improper data handling in network communications. From an attack perspective, this issue maps to ATT&CK technique T1566, specifically focusing on the initial access phase where adversaries exploit network protocols to gather intelligence about target devices. The fix implemented by apple represents a defensive measure that aligns with privacy-enhancing technologies and follows recommendations from privacy-focused security frameworks. Organizations and users should recognize that this vulnerability highlights the importance of regular security updates and the need for robust privacy controls in wireless networking environments, particularly when dealing with mobile devices that continuously broadcast identifying information to maintain connectivity with wireless networks.