CVE-2019-2034 in Android
Summary
by MITRE
In rw_i93_sm_read_ndef of rw_i93.cc, there is a possible out-of-bounds write due to an integer overflow. This could lead to local escalation of privilege in the NFC process with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android. Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-122035770.
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Analysis
by VulDB Data Team • 05/31/2020
The vulnerability identified as CVE-2019-2034 resides within the NFC subsystem of Android operating systems, specifically in the rw_i93_sm_read_ndef function located in the rw_i93.cc source file. This flaw represents a critical security issue that could enable local privilege escalation within the NFC process, potentially allowing attackers to gain elevated system privileges without requiring additional execution privileges. The vulnerability manifests as a possible out-of-bounds write condition that stems from an integer overflow, making it particularly dangerous as it can lead to arbitrary code execution within the privileged NFC context. The affected Android versions span from 7.0 through 9.0, indicating a wide range of devices that could be compromised by this vulnerability.
The technical root cause of this vulnerability can be traced to improper input validation and integer overflow handling within the NFC protocol implementation. When processing NFC data structures, specifically those related to ISO/IEC 15693 smart card communication, the system fails to properly validate the size parameters of incoming data. This integer overflow condition occurs when the system attempts to calculate memory allocation or buffer boundaries based on potentially malicious input values that exceed the maximum representable integer values. The resulting overflow can cause the system to write data beyond the intended memory boundaries, creating opportunities for memory corruption that could be exploited to execute arbitrary code. This type of vulnerability aligns with CWE-190, which specifically addresses integer overflow and wraparound conditions.
The operational impact of CVE-2019-2034 extends beyond simple data corruption, as it enables local privilege escalation within the NFC subsystem. An attacker needing only user interaction to exploit this vulnerability could potentially gain elevated privileges that would allow them to access sensitive system resources, modify system files, or execute commands with the privileges of the NFC service process. The attack vector requires user interaction, meaning a malicious actor could trick a user into performing a specific action such as scanning an NFC tag or connecting to an NFC-enabled device that contains malicious data. This attack model aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and T1550.003, which covers 'Use Alternate Authentication Material: Appropriate Access Token'. The vulnerability's presence in the NFC subsystem is particularly concerning because NFC services typically run with elevated privileges and have access to sensitive system functions.
Mitigation strategies for this vulnerability should focus on both immediate patching and defensive measures. The primary solution involves applying the security patches released by Google for the affected Android versions, which typically include bounds checking mechanisms and proper integer overflow handling in the NFC subsystem. System administrators should also implement monitoring for unusual NFC activity patterns and consider disabling NFC functionality when not required for specific use cases. The vulnerability's classification as a local privilege escalation issue means that additional defense-in-depth measures such as application sandboxing, restricted NFC permissions, and regular security audits of NFC-related code should be implemented. Organizations should also ensure that their Android devices are kept up to date with the latest security patches and consider implementing mobile device management solutions that can automatically deploy security updates to prevent exploitation of this and similar vulnerabilities.