CVE-2020-0139 in Android
Summary
by MITRE
In NDEF_MsgValidate of ndef_utils.c, there is a possible out of bounds read due to an integer overflow. This could lead to local information disclosure if a malformed NFC tag is provided by the firmware. System execution privileges are needed and user interaction is not needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-145520471
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0139 resides within the NDEF message validation functionality of Android's NFC subsystem, specifically in the ndef_utils.c source file. This issue manifests as a potential out of bounds read condition that arises from an integer overflow during the processing of NFC tag data. The flaw occurs during the validation of NDEF (NFC Data Exchange Format) messages, which are fundamental to how NFC devices communicate and exchange information with other NFC-enabled devices. The integer overflow vulnerability represents a critical security weakness that can be exploited to access memory locations beyond the intended bounds of the data structure being processed.
The technical implementation of this vulnerability involves the manipulation of integer values during the parsing of NFC tag content where the system fails to properly validate the size parameters of incoming data. When malformed NFC tags are processed, the integer overflow can cause the system to interpret memory locations incorrectly, potentially leading to information disclosure through the reading of adjacent memory regions. This particular flaw affects Android 10 systems and is classified as a local information disclosure vulnerability. The vulnerability requires system execution privileges for exploitation, meaning that an attacker would need to have elevated privileges within the system to leverage this weakness effectively. However, the absence of user interaction requirements makes this vulnerability particularly concerning as it can be exploited automatically when NFC tags are processed by the system.
The operational impact of CVE-2020-0139 extends beyond simple information disclosure, as it represents a potential pathway for more sophisticated attacks within the NFC processing pipeline. Attackers could potentially extract sensitive system information, configuration data, or other confidential information stored in memory adjacent to the vulnerable data structures. This vulnerability aligns with CWE-190, which describes integer overflow conditions that can lead to memory corruption and information disclosure. The vulnerability also maps to ATT&CK technique T1059.005, which covers the use of command and scripting interpreters, as the exploitation could potentially lead to further system compromise through the information gathered from memory reads. The nature of the vulnerability suggests that it could be particularly dangerous in environments where NFC is actively used for device authentication, payment processing, or other security-sensitive applications.
Mitigation strategies for this vulnerability should focus on implementing proper integer overflow checks within the NDEF message validation routines, ensuring that size parameters are validated before any memory operations are performed. The Android security team addressed this issue through a system update that included bounds checking mechanisms and proper integer overflow protection in the ndef_utils.c file. Organizations should ensure that all Android 10 devices are updated with the latest security patches, particularly in environments where NFC functionality is heavily utilized. Additional defensive measures include implementing NFC tag filtering mechanisms that can identify and reject malformed tags before they reach the vulnerable processing functions, as well as monitoring for unusual NFC activity patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation in security-sensitive code paths, particularly in mobile operating systems where NFC functionality provides a direct interface between hardware and software components.