CVE-2018-9558 in Android
Summary
by MITRE
In rw_t2t_handle_tlv_detect of rw_t2t_ndef.cc, there is a possible out-of-bounds write due to a missing bounds check. This could lead to local escalation of privilege in the NFC kernel 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-112161557.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/18/2020
The vulnerability identified as CVE-2018-9558 represents a critical out-of-bounds write flaw within the NFC kernel component of Android operating systems. This issue resides in the rw_t2t_handle_tlv_detect function located in the rw_t2t_ndef.cc source file, where a fundamental missing bounds check creates an exploitable condition that can lead to privilege escalation. The vulnerability affects multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, indicating a widespread impact across the Android ecosystem. The flaw specifically manifests when processing Type 2 Tag (T2T) NFC tags during NDEF (NFC Data Exchange Format) operations, making it particularly concerning given the prevalence of NFC functionality in modern mobile devices.
The technical nature of this vulnerability stems from inadequate input validation within the NFC tag handling mechanism. When the system processes NFC data structures containing TLV (Type-Length-Value) formatted information, the rw_t2t_handle_tlv_detect function fails to properly validate the boundaries of the data being processed. This missing bounds check allows an attacker to craft malicious NFC tag data that can cause the system to write beyond allocated memory regions. The out-of-bounds write condition creates opportunities for memory corruption that can be leveraged to execute arbitrary code with kernel-level privileges, effectively enabling local privilege escalation without requiring additional execution privileges. According to CWE-129, this vulnerability aligns with improper input validation issues that can lead to buffer overflows and memory corruption scenarios.
The operational impact of this vulnerability is significant as it represents a local privilege escalation vector that can be exploited through NFC interactions. The requirement for user interaction means that an attacker must convince a user to interact with a malicious NFC tag, typically through physical proximity or by placing the tag in a location where the victim's device will encounter it. This attack vector aligns with ATT&CK technique T1059.005, which involves the use of NFC and Bluetooth for malicious purposes. The vulnerability's exploitation potential is particularly concerning because it allows attackers to gain kernel-level privileges, enabling them to bypass system security controls, access sensitive data, and potentially install persistent malware on the device. The Android ID A-112161557 indicates this was properly tracked and addressed by Google's security team, but the widespread affected versions suggest that many devices remained vulnerable for extended periods.
Mitigation strategies for CVE-2018-9558 should focus on both immediate patching and defensive measures. The primary solution involves applying the security patches released by Google as part of their regular Android security updates, which typically include bounds checking mechanisms and input validation improvements. Organizations and users should ensure their devices are updated to the latest Android versions that contain the fix for this vulnerability. Additionally, defensive measures can include implementing NFC security policies that limit NFC functionality in sensitive environments, disabling NFC when not actively needed, and monitoring for suspicious NFC tag interactions. Network administrators should consider deploying mobile device management solutions that can enforce security policies and ensure timely patch deployment across enterprise devices. The vulnerability highlights the importance of secure coding practices in kernel-level components and emphasizes the need for rigorous input validation and bounds checking in all system components that handle external data processing.