CVE-2019-9251 in Android
Summary
by MITRE
In NFC, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-120274615
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9251 resides within the Near Field Communication (NFC) subsystem of Android operating systems, specifically affecting Android 10 and earlier versions. This issue represents a critical security flaw that stems from inadequate input validation mechanisms within the NFC processing pipeline. The vulnerability manifests as a missing bounds check during the handling of NFC data structures, creating a potential avenue for unauthorized information disclosure. The flaw occurs when the system processes NFC data without properly validating the boundaries of memory accesses, leading to potential out-of-bounds read operations that can expose sensitive data stored in memory regions beyond the intended data boundaries.
The technical implementation of this vulnerability involves the NFC service component that handles incoming NFC data packets from external devices or applications. When processing malformed or specially crafted NFC data, the system fails to validate the length or boundaries of the data structure before attempting to read from memory locations. This missing validation allows an attacker to construct specific NFC payloads that, when processed by the vulnerable Android system, trigger memory access violations that result in information disclosure. The vulnerability requires user interaction for exploitation, meaning that a user must intentionally engage with an NFC-enabled device or application for the attack to succeed, typically through NFC handover or direct NFC data exchange scenarios.
The operational impact of CVE-2019-9251 extends beyond simple information disclosure, as it can potentially expose sensitive system information, user data, or cryptographic keys stored in memory. Attackers leveraging this vulnerability can gain insights into the internal state of the NFC subsystem, potentially revealing system configuration details, memory layouts, or other sensitive information that could be used to facilitate further attacks. The requirement for user interaction limits the scope of automated exploitation but does not eliminate the threat, as social engineering campaigns could effectively trick users into interacting with malicious NFC devices or applications. This vulnerability directly maps to CWE-129, which describes improper validation of array indices, and aligns with ATT&CK technique T1059.005 for the execution of code through NFC-based attack vectors.
Mitigation strategies for this vulnerability encompass both immediate system updates and operational security measures. Android users should immediately install the latest security patches released by Google, which include fixes for the NFC subsystem's bounds checking mechanisms. System administrators should implement NFC device management policies that restrict NFC functionality in high-security environments and monitor for suspicious NFC activity. Additionally, organizations should consider deploying network segmentation controls to limit the potential impact of NFC-based attacks and ensure that NFC-enabled devices are properly configured with appropriate security settings. The vulnerability underscores the importance of robust input validation and bounds checking in mobile operating systems, particularly in subsystems that handle external data inputs like NFC, which are inherently more exposed to potential attack vectors due to their wireless nature and user interaction requirements.