CVE-2016-3882 in Android
Summary
by MITRE
Off-by-one error in server/wifi/anqp/VenueNameElement.java in Wi-Fi in Android 6.x before 2016-10-01 and 7.0 before 2016-10-01 allows remote attackers to cause a denial of service (reboot) via an access point that provides a crafted (1) Venue Group or (2) Venue Type value, aka internal bug 29464811.
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Analysis
by VulDB Data Team • 09/22/2022
The vulnerability identified as CVE-2016-3882 represents a critical off-by-one error within the Wi-Fi subsystem of Android operating systems, specifically affecting versions 6.x and 7.0 prior to October 1, 2016. This flaw resides in the server/wifi/anqp/VenueNameElement.java component which processes Anqp (Access Network Query Protocol) elements during Wi-Fi network association procedures. The vulnerability manifests when an access point broadcasts maliciously crafted Venue Group or Venue Type values that trigger buffer boundary violations in the Android Wi-Fi framework. Such errors typically occur when the system attempts to process data that exceeds allocated memory boundaries, creating opportunities for memory corruption that can escalate into system instability.
The technical implementation of this vulnerability stems from improper bounds checking within the ANQP element parsing logic. When the Android Wi-Fi stack encounters a malformed Venue Group or Venue Type value, the off-by-one error causes the system to read or write data beyond the intended memory buffer boundaries. This memory corruption can manifest in various ways including stack corruption, heap corruption, or pointer manipulation that ultimately leads to system crashes. The vulnerability specifically targets the ANQP protocol elements that define venue information for Wi-Fi networks, making it particularly dangerous in environments where attackers can control or influence access point configurations. The flaw operates at the network layer where Wi-Fi association requests are processed, making it possible for remote attackers to exploit the vulnerability without requiring physical access to the device.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable system-wide reboots or crashes that can disrupt network connectivity and compromise device availability. When exploited, the vulnerability can cause Android devices to enter a reboot loop or crash the Wi-Fi subsystem entirely, effectively rendering the device unable to connect to Wi-Fi networks until manually restarted. This creates significant operational concerns for enterprise environments where device availability is critical and for users who rely on consistent network connectivity. The vulnerability's remote exploitability means that attackers can trigger the condition from any location within Wi-Fi range, making it particularly dangerous in public or shared network environments where malicious access points might be deployed. The timing of the vulnerability's exploitation can also be unpredictable, as it may only occur under specific conditions related to the exact values provided in the ANQP elements.
Mitigation strategies for this vulnerability focus on both immediate patching and network monitoring approaches. The primary solution involves applying the security patches released by Google for Android versions 6.x and 7.0, which correct the bounds checking logic in the ANQP processing code. Organizations should prioritize updating their Android devices to versions released after October 1, 2016, when the vulnerability was addressed. Network administrators should also implement monitoring solutions to detect anomalous ANQP element values in Wi-Fi networks, as this can help identify potentially malicious access points before exploitation occurs. Additional defensive measures include configuring Wi-Fi networks to limit association with unknown or untrusted access points and implementing network segmentation to reduce the attack surface. From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and falls under ATT&CK technique T1059 for command and control through network protocols. The vulnerability demonstrates how seemingly minor implementation flaws in network protocol handling can create significant security risks, emphasizing the importance of robust input validation and memory safety practices in mobile operating systems.