CVE-2020-0480 in Android
Summary
by MITRE • 12/15/2020
In callUnchecked of DocumentsProvider.java, there is a possible permissions bypass due to a missing permission check. This could lead to local escalation of privilege allowing a caller to copy, move, or delete files accessible to DocumentsProvider with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-157320716
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability described in CVE-2020-0480 resides within the DocumentsProvider.java component of Android operating systems, specifically affecting Android 11 installations. This flaw represents a critical permissions bypass issue that stems from a missing permission check in the callUnchecked method implementation. The vulnerability manifests as a potential local privilege escalation vector that allows malicious actors to perform unauthorized file operations on the device.
The technical flaw occurs when the DocumentsProvider component fails to properly validate permissions before executing file operations such as copying, moving, or deleting files. This missing permission verification creates a pathway for unauthorized access to files that should otherwise be restricted to specific applications or users. The vulnerability specifically impacts the DocumentsProvider framework which serves as a central interface for file operations within Android's storage system, making it a critical component for exploitation.
From an operational perspective, this vulnerability enables a local attacker to escalate privileges without requiring additional execution privileges or user interaction beyond initial access. The exploit allows for unauthorized modification of files accessible through the DocumentsProvider interface, potentially leading to data theft, system compromise, or complete device control. The requirement for user interaction suggests that while the attack vector may involve some form of initial compromise or social engineering, the actual privilege escalation occurs automatically once the initial access point is established.
The impact of this vulnerability aligns with CWE-284, which addresses improper access control issues in software systems. This classification specifically addresses the problem of insufficient checks or incorrect permissions that allow unauthorized access to system resources. The ATT&CK framework would categorize this vulnerability under privilege escalation techniques, specifically targeting the use of system-level interfaces to gain elevated access rights.
Mitigation strategies for CVE-2020-0480 should focus on implementing proper permission validation within the DocumentsProvider component and ensuring that all file operations undergo thorough access control verification. Android security patches released by Google address this vulnerability by adding the missing permission checks in the callUnchecked method. Organizations should prioritize applying these security updates immediately and consider implementing additional monitoring for unauthorized file operations within the DocumentsProvider framework. Regular security assessments of Android applications that interact with DocumentsProvider should also be conducted to identify potential exploitation vectors and ensure proper implementation of access controls.