CVE-2021-0692 in Android
Summary
by MITRE • 10/06/2021
In sendBroadcastToInstaller of FirstScreenBroadcast.java, there is a possible activity launch due to an unsafe PendingIntent. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-9 Android-10Android ID: A-179289753
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Analysis
by VulDB Data Team • 10/10/2021
The vulnerability identified as CVE-2021-0692 resides within the Android system's FirstScreenBroadcast.java component, specifically in the sendBroadcastToInstaller method. This flaw represents a critical security weakness that allows for potential local privilege escalation without requiring any additional execution privileges or user interaction for exploitation. The vulnerability stems from an unsafe PendingIntent usage pattern that creates an attack surface for malicious actors to manipulate system behavior through carefully crafted broadcast intents.
The technical implementation flaw involves the improper handling of PendingIntent objects within the broadcast mechanism, creating opportunities for unauthorized code execution with elevated privileges. This issue manifests when the system attempts to send broadcasts to installers, but the PendingIntent configuration lacks proper security controls that would normally prevent malicious intent propagation. The vulnerability aligns with CWE-457, which addresses the use of uninitialized or improperly initialized objects in security contexts, and represents a direct violation of secure coding practices for intent handling within Android's security model.
From an operational impact perspective, this vulnerability enables attackers to achieve local privilege escalation, meaning that malicious applications or processes running with standard user privileges could potentially elevate their access level to system-level permissions. The absence of user interaction requirements makes this particularly concerning as it can be exploited automatically without requiring any form of social engineering or user deception. Attackers could leverage this flaw to gain root access to affected Android devices running versions 9, 10, and 11, potentially allowing them to access all device data, install malicious applications, or modify system configurations.
The exploitation of this vulnerability aligns with ATT&CK technique T1068, which involves the use of legitimate credentials or system access to escalate privileges. Security researchers have identified that this flaw represents a classic example of unsafe intent handling where the system fails to properly validate or sanitize PendingIntent parameters before executing them. The vulnerability's impact is further amplified by the fact that it affects multiple Android versions, creating a widespread attack surface across different device ecosystems. Organizations and users should prioritize patching this vulnerability through official Android security updates, as the risk of exploitation increases with the availability of working proof-of-concept implementations in the cybersecurity community. The flaw demonstrates how seemingly routine broadcast mechanisms can become critical attack vectors when proper security controls are not implemented in the PendingIntent handling code, emphasizing the importance of secure intent design patterns in mobile operating systems.