CVE-2021-0686 in Android
Summary
by MITRE • 10/06/2021
In getDefaultSmsPackage of RoleManagerService.java, there is a possible way to get information about the default sms app of a different device user due to a missing permission check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-10Android ID: A-177927831
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/10/2021
The vulnerability identified as CVE-2021-0686 resides within the Android operating system's RoleManagerService component, specifically in the getDefaultSmsPackage method implementation. This flaw represents a critical information disclosure vulnerability that exploits a missing permission check mechanism within the Android framework's user isolation controls. The vulnerability affects Android versions 10 and 11, making it particularly concerning given the widespread deployment of these operating system versions across mobile devices globally. The issue stems from insufficient access control validation when retrieving SMS application default settings, creating a scenario where malicious applications can potentially access sensitive information about other user accounts on the same device.
The technical nature of this vulnerability aligns with CWE-284 Access Control Issues, specifically manifesting as improper access control within the Android system services layer. The RoleManagerService acts as a central authority for managing system roles including SMS applications, yet fails to properly validate whether the requesting process has appropriate authorization to access default SMS package information for other user contexts. This missing permission check creates an attack vector where a malicious application running in one user profile can potentially enumerate and extract information about the default SMS application configured by another user profile, effectively bypassing Android's multi-user security boundaries. The vulnerability operates at the system service level, leveraging the underlying Android framework's user session management mechanisms without requiring any special privileges or user interaction for exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the multi-user security model that Android implements to protect user data isolation. An attacker could potentially gather intelligence about other users' messaging preferences, application configurations, and even infer behavioral patterns based on SMS application choices. This information could serve as a foundation for more sophisticated attacks, including social engineering campaigns or targeted malware delivery. The vulnerability's exploitation requires no additional execution privileges beyond what is normally available to applications, making it particularly dangerous as it can be triggered by any application with basic system access. The lack of user interaction requirements significantly increases the attack surface and makes this vulnerability particularly challenging to detect and prevent in real-world scenarios.
Mitigation strategies for CVE-2021-0686 should prioritize immediate system updates from Google and device manufacturers, as this vulnerability affects core Android framework components that require official patches to address the underlying permission check deficiencies. Organizations should implement robust application whitelisting policies and monitor for suspicious activity related to system service access patterns, particularly around RoleManagerService calls. The vulnerability's classification under ATT&CK technique T1068 Privilege Escalation through System Service Exploitation highlights the need for enhanced monitoring of system service interactions and user context switching behaviors. Device administrators should also consider implementing additional security measures such as application sandboxing and user profile isolation controls to limit potential impact. Regular security assessments should include verification of proper permission enforcement in system service components, and network administrators should monitor for unusual patterns of inter-user data access attempts that could indicate exploitation of this vulnerability.