CVE-2021-0953 in Android
Summary
by MITRE • 12/15/2021
In setOnClickActivityIntent of SearchWidgetProvider.java, there is a possible way to access contacts and history bookmarks without permission due to an unsafe PendingIntent. This could lead to local escalation of privilege with User execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-9Android ID: A-184046278
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Analysis
by VulDB Data Team • 12/22/2021
The vulnerability identified as CVE-2021-0953 resides within the Android search widget implementation, specifically in the setOnClickActivityIntent method of the SearchWidgetProvider.java component. This flaw represents a critical security weakness that allows unauthorized access to sensitive user data including contacts and browsing history bookmarks. The vulnerability stems from the improper handling of PendingIntent objects which are used to launch activities when users interact with search widgets. When an application creates a PendingIntent, it typically specifies the target activity and the intent that should be launched, but in this case the PendingIntent is constructed in a manner that permits arbitrary code execution or data access without proper authorization checks.
The technical root cause of this vulnerability aligns with CWE-377, which addresses unsafe handling of sensitive data in pending intents, and CWE-284, which covers inadequate access control mechanisms. The flaw enables a local privilege escalation scenario where an attacker with user-level execution privileges can exploit this weakness to gain elevated access to personal information. The vulnerability affects multiple Android versions including Android 9, 10, 11, and 12, indicating a widespread impact across the Android ecosystem. The security implications are particularly severe because the PendingIntent construction does not properly validate the source or target of the intent, allowing malicious applications to intercept or manipulate the intent flow to access protected data.
From an operational perspective, this vulnerability represents a significant threat to user privacy and data security as it allows unauthorized access to sensitive information without requiring user interaction. The exploitation process leverages the existing search widget functionality to create a malicious PendingIntent that can access contacts and history bookmarks. This aligns with ATT&CK technique T1068 which involves local privilege escalation through the exploitation of system vulnerabilities. The vulnerability's impact extends beyond simple data theft as it provides attackers with access to potentially sensitive personal information including communication patterns and browsing habits that could be used for further exploitation or social engineering attacks.
The mitigation strategies for CVE-2021-0953 primarily involve applying the latest security patches and updates from Google, which address the unsafe PendingIntent construction by implementing proper permission checks and intent validation mechanisms. System administrators and security teams should prioritize the deployment of these updates across all affected Android devices and ensure that proper security monitoring is in place to detect any suspicious PendingIntent usage patterns. Additionally, users should be educated about the importance of keeping their devices updated and should avoid installing untrusted applications that might exploit this vulnerability. The fix typically involves modifying the PendingIntent creation process to use FLAG_IMMUTABLE or similar protective mechanisms that prevent unauthorized modification of the intent parameters, thereby preventing the escalation of privileges and unauthorized data access that this vulnerability enables.