CVE-2019-2035 in Android
Summary
by MITRE
In rw_i93_sm_update_ndef of rw_i93.cc, there is a possible out-of-bound write due to a missing bounds check. This could lead to local escalation of privilege 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-122320256
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Analysis
by VulDB Data Team • 05/31/2020
The vulnerability described in CVE-2019-2035 represents a critical out-of-bounds write flaw within the Android NFC subsystem, specifically in the rw_i93_sm_update_ndef function located in the rw_i93.cc file. This issue resides in the Near Field Communication (NFC) stack that handles ISO 14443-3A and ISO 15693 protocol implementations. The flaw manifests when processing NDEF (NFC Data Exchange Format) data during the update operation of ISO 14443-3A smart card communication, where the system fails to properly validate the bounds of data being written to memory buffers. This missing bounds check creates a condition where maliciously crafted NFC data could overwrite adjacent memory locations, potentially corrupting critical system structures or executing arbitrary code.
The technical nature of this vulnerability places it squarely within the CWE-787 Out-of-bounds Write category, which is classified as a severe memory safety issue that can lead to privilege escalation. The vulnerability requires no additional execution privileges for exploitation, making it particularly dangerous as it can be triggered through standard NFC communication channels without requiring root access or special user permissions. However, the exploitation process necessitates user interaction, meaning an attacker must present a malicious NFC tag or device to the target Android device for the attack to succeed. This interaction requirement typically involves the user coming into physical proximity with the malicious NFC device or tag, which aligns with the ATT&CK technique T1550.001 for Use of Valid Credentials and T1059.001 for Command and Scripting Interpreter, though the latter is more relevant to the privilege escalation aspect.
The operational impact of this vulnerability extends across multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, representing a broad attack surface that affects millions of devices. When exploited successfully, this vulnerability could enable local privilege escalation, allowing an attacker to gain elevated system privileges and potentially compromise the entire device. The attack vector through NFC communication means that users could be compromised simply by having a malicious NFC device in their vicinity or by interacting with malicious NFC tags in public spaces. This represents a significant risk to both personal privacy and device security, as the attacker could potentially access sensitive data, modify system files, or install malicious applications. The vulnerability's location within the NFC stack also means that it could be exploited to bypass security mechanisms that rely on proper NFC data handling, including secure element operations and trusted application communications.
Mitigation strategies for CVE-2019-2035 primarily focus on applying the security patches released by Google as part of their Android security bulletins, specifically addressing the bounds checking issues in the NFC subsystem. Organizations and users should ensure their Android devices are updated to the latest security patches, particularly those released in the Q1 2019 security updates. Additionally, system administrators should consider implementing NFC security policies that limit NFC functionality in high-security environments, disable NFC when not actively needed, and monitor for suspicious NFC activity. The vulnerability highlights the importance of secure coding practices in mobile operating systems, particularly around memory management and bounds checking in protocol handlers. Security professionals should also consider deploying network-based intrusion detection systems that can monitor for potential NFC-based attacks and implement device management policies that enforce regular security updates and disable unnecessary NFC features in enterprise environments. The fix typically involves implementing proper input validation and bounds checking in the rw_i93_sm_update_ndef function to prevent unauthorized memory writes, which aligns with the security principle of least privilege and defense in depth strategies recommended by various cybersecurity frameworks including NIST SP 800-53 and ISO/IEC 27001.