CVE-2020-0243 in Android
Summary
by MITRE
In clearPropValue of MediaAnalyticsItem.cpp, there is a possible use-after-free due to improper locking. This could lead to local escalation of privilege in the media server with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-9 Android-10 Android-8.0 Android-8.1Android ID: A-151644303
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Analysis
by VulDB Data Team • 08/12/2020
The vulnerability identified as CVE-2020-0243 represents a critical use-after-free condition within the Android media server component, specifically in the clearPropValue function of MediaAnalyticsItem.cpp. This flaw exists in the media analytics subsystem that processes and handles media-related data within the Android operating system. The issue manifests when the system improperly manages memory locking mechanisms during the processing of media analytics properties, creating a scenario where freed memory locations can be accessed and potentially reused by subsequent operations. The vulnerability affects multiple Android versions including Android 8.0, 8.1, 9, and 10, indicating a widespread impact across several major Android releases. This represents a serious security concern as it allows for privilege escalation without requiring any additional execution privileges or user interaction, making it particularly dangerous for exploitation in both targeted and automated attack scenarios.
The technical implementation of this vulnerability stems from inadequate synchronization mechanisms within the media analytics processing code. When clearPropValue function executes, it fails to properly acquire and maintain appropriate locks during memory operations, leading to a race condition scenario where memory deallocation occurs before all references to that memory are cleared. This use-after-free condition creates a potential exploitation vector where malicious code could manipulate the freed memory location to execute arbitrary code with elevated privileges. The vulnerability specifically targets the media server process which runs with elevated privileges, making the local privilege escalation particularly severe. According to CWE standards, this maps to CWE-416 Use After Free, a well-documented vulnerability pattern where software continues to reference memory after it has been freed, leading to unpredictable behavior and potential code execution.
The operational impact of CVE-2020-0243 extends beyond simple privilege escalation as it provides attackers with a pathway to gain unauthorized access to sensitive system resources and capabilities. Since the media server typically handles multimedia processing tasks including audio and video encoding/decoding, the privilege escalation could enable attackers to access device storage, modify system configurations, or potentially intercept sensitive media data. The lack of user interaction requirement makes this vulnerability particularly concerning for automated exploitation, as it can be triggered through normal media processing activities without requiring user engagement. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under privilege escalation tactics, specifically targeting the 'Local Privilege Escalation' and 'Exploitation for Privilege Escalation' domains. The vulnerability's impact is further amplified by the fact that the media server process typically runs with high privileges, potentially providing access to system-level resources and data that would otherwise be restricted.
Mitigation strategies for CVE-2020-0243 should focus on implementing proper memory locking mechanisms and synchronization primitives within the media analytics subsystem. Android security patches addressing this vulnerability typically involve strengthening the locking mechanisms in the clearPropValue function to ensure that memory operations are properly synchronized and that freed memory locations cannot be accessed until all references are properly cleared. System administrators should prioritize applying the latest security updates from Android vendors, as this vulnerability was addressed through official security patches released by Google. Additional protective measures include implementing application sandboxing, monitoring media server processes for unusual behavior, and conducting regular security audits of media processing components. Organizations should also consider implementing network-level monitoring to detect potential exploitation attempts and maintain comprehensive logging of media server activities to identify any anomalous behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper memory management in system-level components and the need for robust synchronization mechanisms in multi-threaded environments.