CVE-2021-1024 in Android
Summary
by MITRE • 12/15/2021
In onEventReceived of EventResultPersister.java, there is a possible intent redirection due to a confused deputy. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12Android ID: A-191283525
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Analysis
by VulDB Data Team • 12/22/2021
The vulnerability identified as CVE-2021-1024 represents a critical security flaw in Android's event handling mechanism that could enable local privilege escalation. This issue resides within the EventResultPersister.java component where the onEventReceived method processes incoming events without proper validation of intent origins. The vulnerability stems from a confused deputy problem where the system fails to properly verify the authenticity of intents being processed, allowing malicious actors to manipulate the event flow and potentially execute arbitrary code with system-level privileges.
The technical implementation of this vulnerability involves a failure in intent verification mechanisms that should normally prevent unauthorized components from masquerading as legitimate system services. When events are received through the EventResultPersister, the system does not adequately validate whether the originating intent comes from trusted sources or has been properly authenticated. This confusion between legitimate and malicious intents creates a pathway for privilege escalation attacks where an attacker can craft specially crafted events that appear to originate from system components, thereby bypassing normal security boundaries and gaining elevated execution privileges.
From an operational perspective, this vulnerability presents significant risk to Android devices as it requires no user interaction for exploitation, making it particularly dangerous in environments where malicious actors have local access to devices. The attack vector leverages the system's trust in internal event processing mechanisms, allowing attackers to potentially gain system-level execution privileges without requiring physical access or complex social engineering. The impact extends beyond simple privilege escalation to potentially enable full device compromise, as system execution privileges would allow attackers to modify critical system components, access sensitive data, or install persistent backdoors.
The vulnerability aligns with CWE-225, which addresses the confusion between legitimate and malicious intent in software systems, and relates to ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation." The affected Android version 12 represents a significant portion of devices that could be impacted, given the widespread adoption of this platform version. Security researchers have noted that the vulnerability is particularly concerning because it operates at the system level and exploits fundamental trust mechanisms that should prevent such unauthorized privilege escalation. Organizations should implement immediate mitigations including system updates, enhanced intent validation procedures, and monitoring for suspicious event processing patterns. The fix typically involves strengthening the intent verification process in EventResultPersister.java to ensure that all incoming events are properly authenticated before being processed, thereby preventing the confused deputy scenario that enables privilege escalation attacks.