CVE-2021-39799 in Android
Summary
by MITRE • 04/12/2022
In AttributionSource of AttributionSource.java, there is a possible permission bypass due to improper input validation. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12 Android-12LAndroid ID: A-200288596
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Analysis
by VulDB Data Team • 04/18/2022
The vulnerability identified as CVE-2021-39799 resides within the AttributionSource component of Android's system architecture, specifically in the AttributionSource.java file. This flaw represents a critical permission bypass issue that stems from inadequate input validation mechanisms within the attribution system. The vulnerability affects Android 12 and Android 12L versions, with the Android ID A-200288596 documenting the specific security concern. The root cause lies in how the system processes attribution source parameters, creating a pathway for malicious actors to exploit improper validation checks that should have prevented unauthorized access to system resources.
The technical implementation of this vulnerability allows for local privilege escalation without requiring any additional execution privileges or user interaction for successful exploitation. This means that an attacker with local access to a device can leverage this flaw to gain elevated system privileges, effectively bypassing the normal permission controls that protect sensitive system components. The flaw operates at the system level where attribution sources are processed, potentially allowing unauthorized modification of system attributes or access to restricted functionalities that should only be available to privileged processes.
From an operational impact perspective, this vulnerability creates a significant security risk for Android devices running the affected versions, as it enables attackers to escalate their privileges locally without requiring additional attack vectors or user engagement. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited automatically when the device is in use. This type of local privilege escalation typically allows attackers to gain access to system-level resources, potentially leading to complete device compromise, data exfiltration, or further exploitation of other system components.
Security professionals should consider this vulnerability in the context of the CWE-20 standard for improper input validation, which directly relates to the flawed validation mechanisms within the AttributionSource component. The ATT&CK framework would categorize this vulnerability under privilege escalation techniques, specifically leveraging system-level weaknesses to gain elevated access. Mitigation strategies should include immediate patching of affected Android versions, implementation of additional input validation controls within attribution systems, and monitoring for unauthorized privilege escalation attempts. Organizations should also consider deploying additional security controls such as application whitelisting and enhanced system integrity monitoring to detect potential exploitation attempts. The vulnerability highlights the critical importance of robust input validation in system-level components and demonstrates how seemingly minor validation flaws can lead to significant security implications across the entire operating system.