CVE-2021-0996 in Android
Summary
by MITRE • 12/15/2021
In nfaHciCallback of HciEventManager.cpp, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure over NFC with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-181346545
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0996 resides within the NFC (Near Field Communication) subsystem of Android 12 operating on devices that utilize the nfaHciCallback function within the HciEventManager.cpp component. This represents a critical security flaw that stems from inadequate input validation mechanisms, specifically a missing bounds check during the processing of NFC communication events. The vulnerability is categorized under CWE-129 as an implementation error that allows for improper input validation, which directly enables potential buffer overflow conditions through out-of-bounds memory reads.
The technical flaw manifests when the nfaHciCallback function processes incoming NFC data through the HciEventManager component without sufficient validation of array indices or buffer boundaries. This missing bounds check creates an exploitable condition where malicious NFC communications could trigger memory access violations that result in information disclosure. The vulnerability requires System execution privileges for exploitation, indicating that an attacker must already possess elevated privileges within the Android system to leverage this flaw effectively. However, the potential for information disclosure makes this particularly concerning as it could expose sensitive system data to unauthorized parties.
From an operational impact perspective, this vulnerability presents a significant risk to Android 12 devices that rely on NFC functionality for various security and communication purposes. The local information disclosure capability means that an attacker with system-level privileges could potentially access confidential data stored within the NFC subsystem memory spaces. This could include sensitive communication protocols, device identifiers, or other system-related information that could be leveraged for further attacks or system compromise. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1566.001 for spearphishing attachment, as it could be exploited through NFC-based attack vectors that require system-level access to function effectively.
The exploitation of this vulnerability requires an attacker to already possess system execution privileges, which places it in the category of post-exploitation vulnerabilities rather than initial access vectors. However, the information disclosure aspect makes it particularly dangerous as it could provide attackers with additional system intelligence that could be used for privilege escalation or lateral movement within the device. Security professionals should note that this vulnerability demonstrates the importance of proper input validation in system-level components, particularly those handling communication protocols that may be exposed to external devices. The Android security model's reliance on proper bounds checking in system components underscores the necessity for comprehensive code review processes and adherence to secure coding practices.
Mitigation strategies for CVE-2021-0996 should focus on implementing proper bounds checking mechanisms within the HciEventManager.cpp component and ensuring that all NFC data processing functions validate array indices and buffer boundaries before memory access operations. Android security patches addressing this vulnerability would typically include enhanced input validation routines and potentially updated NFC stack implementations that prevent out-of-bounds read conditions. Organizations should prioritize patching affected Android 12 devices and consider implementing additional monitoring for suspicious NFC communication patterns that could indicate exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date security measures in mobile operating systems where communication protocols like NFC are integral to device functionality.