CVE-2019-9240 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-121150966
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9240 resides within the Near Field Communication (NFC) subsystem of Android operating systems, specifically affecting Android 10 and earlier versions. This issue represents a classic out-of-bounds read condition that occurs when the NFC service fails to properly validate input data before processing it. The vulnerability is categorized under CWE-129 as an insufficient bounds check, which is a fundamental security flaw that allows malicious actors to access memory locations beyond the intended boundaries of allocated buffers.
The technical implementation of this vulnerability stems from inadequate input validation within the NFC processing pipeline where the system does not properly verify the size or content of incoming NFC data packets before attempting to read from memory locations. When a maliciously crafted NFC packet is received and processed, the missing bounds check allows the system to read data from memory regions that should not be accessible, potentially exposing sensitive information stored in adjacent memory locations. This type of vulnerability falls under the ATT&CK technique T1059.007 for execution through script-based payloads and T1005 for data from local system.
Exploitation of this vulnerability requires user interaction as the malicious NFC packet must be presented to the device for processing, typically through physical proximity or NFC-enabled device pairing. The attack vector relies on social engineering or physical access scenarios where an attacker can present a crafted NFC payload to a target device. While no additional execution privileges are required beyond normal NFC processing capabilities, the vulnerability can lead to local information disclosure, potentially exposing confidential data such as user credentials, application data, or system memory contents. The impact is limited to information disclosure rather than arbitrary code execution, but the exposure of sensitive memory contents can still provide attackers with valuable information for further exploitation attempts.
The mitigation strategies for CVE-2019-9240 primarily involve applying the security patches released by Google as part of the Android security updates, specifically addressing the bounds checking deficiencies in the NFC subsystem. Organizations should ensure their Android devices are updated to the latest security patches, with particular attention to Android 10 and earlier versions that remain vulnerable. Additionally, implementing NFC security policies that restrict NFC functionality in sensitive environments, disabling NFC when not actively needed, and educating users about the risks of interacting with unknown NFC devices can provide additional layers of protection. The vulnerability serves as a reminder of the importance of proper input validation in security-critical subsystems and demonstrates how seemingly minor implementation flaws can lead to significant information disclosure risks in mobile platforms.