CVE-2019-9309 in Android
Summary
by MITRE
In NFC, there is a possible out of bounds write due to a missing bounds check. This could lead to a to local escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-117985575
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Analysis
by VulDB Data Team • 09/12/2020
The vulnerability identified as CVE-2019-9309 represents a critical out-of-bounds write flaw within the Near Field Communication subsystem of Android operating systems. This issue resides in the NFC implementation where insufficient bounds checking allows for memory corruption that can be exploited to achieve privilege escalation. The vulnerability affects Android 10 and is tracked under Android ID A-117985575, demonstrating the severity and widespread impact across the Android ecosystem. The flaw specifically manifests when processing NFC data structures without proper validation of array boundaries or buffer limits, creating opportunities for malicious actors to manipulate memory layout and execute arbitrary code with elevated privileges.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array indices, and CWE-787, which covers out-of-bounds write conditions. These weaknesses directly enable an attacker to manipulate memory regions beyond their intended boundaries, potentially overwriting critical system data structures or executable code segments. The exploitation requires user interaction, typically through NFC data transmission or device pairing scenarios, making it particularly concerning for mobile environments where users frequently engage with NFC-enabled applications and services. The attack vector leverages the NFC subsystem's handling of malformed or specially crafted data packets that bypass normal input validation mechanisms.
From an operational perspective, this vulnerability creates a significant risk for privilege escalation attacks that can be executed without requiring additional execution privileges or root access. The local nature of the exploit means that an attacker must first gain access to a device through NFC interaction, but once successful, they can elevate their privileges to system-level access. This capability allows for complete compromise of the device's security model, enabling access to sensitive user data, cryptographic keys, and system resources. The vulnerability's impact extends beyond individual device compromise to potentially enable large-scale attacks against connected NFC ecosystems, particularly in enterprise environments where NFC is used for access control or authentication systems.
The exploitation process typically involves crafting malicious NFC data that triggers the out-of-bounds write condition when processed by the NFC subsystem. This requires understanding of the target device's memory layout and the specific NFC data structures handled by the vulnerable code paths. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the execution of malicious code with elevated privileges. Mitigation strategies include implementing proper bounds checking in all NFC data processing routines, applying security patches from Google's Android security updates, and implementing network segmentation to limit NFC attack surfaces. Organizations should prioritize immediate patch deployment and consider additional security controls such as NFC access restrictions in enterprise environments to prevent unauthorized exploitation of this vulnerability.