CVE-2012-3725 in iOS
Summary
by MITRE
The DNAv4 protocol implementation in the DHCP component in Apple iOS before 6 sends Wi-Fi packets containing a MAC address of a host on a previously used network, which might allow remote attackers to obtain sensitive information about previous device locations by sniffing an unencrypted Wi-Fi network for these packets.
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Analysis
by VulDB Data Team • 04/13/2021
The vulnerability described in CVE-2012-3725 represents a significant privacy and security flaw within Apple iOS devices running versions prior to iOS 6. This issue specifically affects the Dynamic Host Configuration Protocol implementation within the device's Wi-Fi networking stack, where the system fails to properly sanitize network communication data when transitioning between different wireless networks. The flaw manifests in the DNAv4 protocol handling within the DHCP component, creating a persistent identifier that can be exploited by malicious actors monitoring network traffic.
The technical implementation of this vulnerability stems from how iOS devices manage MAC address information during DHCP handshakes when connecting to Wi-Fi networks. When a device connects to a new network after previously using another network, the system retains and transmits certain network identifiers from the previous connection. This behavior violates fundamental principles of network privacy and device anonymity, as the MAC address information becomes embedded in Wi-Fi management frames that are broadcast unencrypted across the wireless medium. The vulnerability is classified under CWE-200 as exposure of sensitive information and aligns with ATT&CK technique T1566 for credential access through network sniffing.
The operational impact of this vulnerability extends beyond simple location tracking, creating potential for broader reconnaissance activities by threat actors. An attacker positioned within range of an unencrypted Wi-Fi network can capture these packets and extract historical location data about the device user, including information about previously visited networks and locations. This creates a persistent tracking mechanism that operates independently of the device's active network connections, effectively allowing continuous monitoring of user movement patterns and network usage history. The vulnerability is particularly concerning in public Wi-Fi environments where network traffic is often unencrypted and accessible to multiple parties.
Mitigation strategies for this vulnerability require both device-level and network-level interventions. Apple addressed this issue by implementing proper MAC address randomization and ensuring that DHCP responses do not carry stale network identifiers from previous connections. Network administrators should enforce encrypted Wi-Fi networks using WPA2 or stronger encryption protocols to prevent passive monitoring of management frames. Additionally, organizations should implement network segmentation and monitoring to detect unusual DHCP traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper information hygiene in network protocols and the need for comprehensive testing of privacy implications in mobile operating system components. This issue serves as a reminder of how seemingly minor implementation details in network protocols can create significant privacy exposures that persist across network transitions and user sessions.