CVE-2019-2011 in Android
Summary
by MITRE
In readNullableNativeHandleNoDup of Parcel.cpp, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-8.0 Android-8.1 Android-9Android ID: A-120084106
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-2011 resides within the Android operating system's Binder transaction mechanism, specifically in the readNullableNativeHandleNoDup function located in Parcel.cpp. This flaw represents a critical security issue that affects Android versions 8.0, 8.1, and 9.0, with the Android ID A-120084106 assigned to track the vulnerability. The core problem manifests as a missing bounds check that allows for out-of-bounds write operations, fundamentally compromising the integrity of the system's memory management.
The technical implementation of this vulnerability stems from improper validation of handle counts during parcel deserialization processes. When the system processes incoming Binder transactions containing native handles, the readNullableNativeHandleNoDup function fails to verify that the number of handles being read does not exceed predetermined limits. This omission creates a scenario where maliciously crafted IPC messages can trigger memory corruption by writing beyond allocated buffer boundaries. The vulnerability operates at the kernel level within the Android runtime environment, making it particularly dangerous as it can be exploited without requiring any special privileges or user interaction.
The operational impact of CVE-2019-2011 extends far beyond typical security concerns, as it enables local privilege escalation with no additional execution privileges required. An attacker who gains access to a regular application context can potentially leverage this vulnerability to elevate their privileges to that of the system itself. This escalation occurs through the exploitation of the out-of-bounds write condition which can be manipulated to overwrite critical system memory regions, including those controlling access permissions and privilege levels. The vulnerability aligns with CWE-129, which addresses improper validation of array indices, and more specifically with CWE-787, concerning out-of-bounds write conditions. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, where adversaries leverage software vulnerabilities to gain elevated system privileges.
The exploitation of this vulnerability requires no user interaction, making it particularly concerning as it can be triggered automatically when the system processes maliciously crafted IPC messages. This characteristic places the vulnerability in the category of "zero-click" exploits, where the attack surface is maximized and the attack vector is minimized. The affected Android versions represent a significant portion of devices in the field, as Android 8.0 and 9.0 were widely deployed across various manufacturers' device lines. The lack of requirement for additional execution privileges means that any application with the ability to send Binder transactions can potentially exploit this vulnerability, creating a broad attack surface that spans across multiple application categories and device types.
Mitigation strategies for CVE-2019-2011 primarily focus on the immediate deployment of security patches provided by Google through their regular Android security bulletins. Organizations should prioritize updating their Android devices to versions containing the fix for this vulnerability, as the patch addresses the root cause by implementing proper bounds checking in the readNullableNativeHandleNoDup function. Additionally, system administrators should implement monitoring solutions that can detect anomalous Binder transaction patterns that might indicate exploitation attempts. The mitigation approach aligns with security best practices outlined in the NIST Cybersecurity Framework, particularly in the areas of vulnerability management and incident response. Organizations should also consider implementing application sandboxing measures and network segmentation to limit the potential impact of successful exploitation attempts, although the nature of this vulnerability makes such measures secondary to the primary patch deployment strategy.