CVE-2021-0959 in Android
Summary
by MITRE • 01/14/2022
In jit_memory_region.cc, there is a possible bypass of memory restrictions due to a logic error in the code. This could lead to local escalation of privilege with User execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-200284993
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-0959 resides within the Android operating system's just-in-time compilation memory management subsystem, specifically in the jit_memory_region.cc source file. This flaw represents a critical security weakness that allows unauthorized privilege escalation through a logic error in memory restriction enforcement mechanisms. The vulnerability affects Android 12 systems and is catalogued under Android ID A-200284993, indicating its severity and the need for immediate attention from device manufacturers and security professionals.
The technical flaw stems from a logic error in the memory region management code that governs how just-in-time compiled code segments are allocated and restricted within memory space. When the JIT compiler processes code, it must enforce strict memory boundaries to prevent code from accessing unauthorized memory regions or executing with elevated privileges. The logic error in question allows malicious code to bypass these memory restrictions through a specific sequence of operations that the original code path fails to properly validate. This creates a scenario where an attacker with standard user execution privileges can manipulate memory allocation patterns to gain access to restricted memory regions that should normally be off-limits to regular applications.
The operational impact of this vulnerability is significant as it enables local privilege escalation without requiring user interaction or additional attack vectors. An attacker who has already gained user-level access to an Android device can exploit this vulnerability to elevate their privileges to system level, potentially gaining access to sensitive system resources, cryptographic keys, or other privileged operations. The vulnerability's local nature means that exploitation does not require network connectivity or external attack surfaces, making it particularly dangerous as it can be leveraged by malware already present on the device. This type of vulnerability directly impacts the Android system's memory safety model and can compromise the integrity of the entire operating system's privilege separation mechanisms.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a specific instance of inadequate privilege management within the Android JIT compilation framework. From an ATT&CK perspective, this flaw maps to privilege escalation techniques under the T1068 category, specifically targeting local privilege escalation through memory corruption or manipulation. The exploitability of this vulnerability is enhanced by the fact that it requires no user interaction, making it particularly dangerous for mobile environments where users may unknowingly install malicious applications that can immediately leverage this privilege escalation mechanism. Security professionals should prioritize patching this vulnerability as it represents a fundamental weakness in Android's memory protection architecture that could enable complete system compromise.
The mitigation strategy for this vulnerability involves implementing the official Android security patches released by Google, which typically include code modifications to correct the memory restriction logic error. Organizations should also consider implementing additional security monitoring to detect unusual memory allocation patterns that might indicate exploitation attempts. Device manufacturers should ensure timely deployment of security updates and maintain comprehensive vulnerability management processes that include regular security assessments of JIT compilation components. The vulnerability serves as a reminder of the critical importance of memory safety mechanisms in modern operating systems and the potential consequences of logic errors in privilege management code.