CVE-2016-3761 in Android
Summary
by MITRE
NfcService.java in NFC in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01 allows attackers to obtain sensitive foreground-application information via a crafted background application, aka internal bug 28300969.
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Analysis
by VulDB Data Team • 02/22/2019
The vulnerability described in CVE-2016-3761 represents a critical information disclosure flaw within the Android NFC service implementation that affects multiple versions of the Android operating system. This weakness resides in the NfcService.java component which governs Near Field Communication functionality, specifically exposing a design flaw that permits background applications to access foreground application data through improper permission handling and information flow control mechanisms. The vulnerability manifests when a malicious background application attempts to gather sensitive information from foreground applications, creating an unauthorized data leakage channel that undermines the fundamental security boundaries between applications.
The technical root cause of this vulnerability stems from insufficient access controls and privilege escalation mechanisms within the NFC service architecture. When applications interact with NFC services, the system should enforce strict security boundaries to prevent background applications from accessing foreground application context and data. However, the flaw allows unauthorized information retrieval through crafted NFC interactions that bypass normal security checks. This issue falls under the CWE-200 category of "Information Exposure" and specifically relates to improper information flow control that enables unauthorized access to sensitive foreground application information. The vulnerability demonstrates a failure in the principle of least privilege where background applications can potentially access foreground application context, violating the core security model of Android's application sandboxing.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to gather potentially sensitive data from running applications without user consent or explicit permission. Attackers can leverage this weakness by installing a malicious background application that monitors NFC interactions and extracts information from foreground applications during NFC transactions. This capability could be exploited to obtain user credentials, personal data, financial information, or other sensitive application context that should remain protected within the secure boundaries of individual applications. The vulnerability is particularly concerning because it operates silently in the background without requiring user interaction or explicit permissions, making it difficult to detect and prevent through conventional security measures.
Mitigation strategies for this vulnerability require immediate system updates and patches from device manufacturers, as the flaw exists at the core Android framework level rather than in individual applications. Users should ensure their devices are updated to the latest Android versions that contain the patched NfcService implementation, specifically versions 4.4.4, 5.0.2, 5.1.1, and 6.x releases that address this specific vulnerability. Security researchers and organizations should implement network monitoring to detect unusual NFC activity patterns that might indicate exploitation attempts, while also reviewing application permissions and NFC usage in mobile device management policies. The vulnerability also highlights the importance of proper input validation and access control mechanisms in system-level services, aligning with ATT&CK technique T1059.007 for command and scripting interpreter usage and T1566.001 for malicious file execution in mobile environments where NFC interactions can serve as attack vectors. Organizations should consider implementing additional application sandboxing measures and regular security assessments of NFC-related functionality to prevent similar vulnerabilities from emerging in other system components.