CVE-2023-21092 in Android
Summary
by MITRE • 04/19/2023
In retrieveServiceLocked of ActiveServices.java, there is a possible way to dynamically register a BroadcastReceiver using permissions of System App due to improper input validation. 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-12 Android-12L Android-13Android ID: A-242040055
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Analysis
by VulDB Data Team • 09/10/2025
The vulnerability identified as CVE-2023-21092 resides within the Android system's ActiveServices.java component, specifically in the retrieveServiceLocked method where improper input validation allows for unauthorized dynamic registration of BroadcastReceivers. This flaw represents a critical security weakness that enables malicious applications to leverage system-level permissions without requiring additional privileges or user interaction. The vulnerability affects multiple Android versions including Android 11, 12, 12L, and 13, indicating a widespread impact across the Android ecosystem. The issue stems from insufficient validation of input parameters during the service retrieval process, creating a pathway for privilege escalation through improper permission handling.
The technical implementation of this vulnerability allows an attacker to register a BroadcastReceiver with system app permissions by exploiting the flawed input validation mechanism. This occurs when the system fails to properly verify the authenticity and authorization level of components attempting to register for broadcast events. The flaw operates at the system level where Android's service management mechanism permits unauthorized registration of broadcast receivers, effectively bypassing normal permission boundaries that should prevent non-system applications from accessing system-level functionality. This type of vulnerability falls under CWE-20, representing improper input validation, and aligns with ATT&CK technique T1068, which involves exploiting legitimate credentials and system privileges for unauthorized access.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides a pathway for attackers to gain unauthorized access to system-level functionality without requiring additional execution privileges. The absence of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited automatically without user involvement. An attacker could potentially register malicious broadcast receivers that intercept system broadcasts, access sensitive system information, or manipulate system behavior in ways that compromise overall device security. This vulnerability essentially undermines the Android permission model by allowing non-system applications to assume system-level privileges through the manipulation of the service registration process.
Mitigation strategies for CVE-2023-21092 should focus on implementing stricter input validation within the ActiveServices.java component and enhancing the permission checking mechanisms during broadcast receiver registration. Android security updates should address the root cause by ensuring proper validation of service registration requests and implementing additional checks to prevent unauthorized permission delegation. System administrators and device manufacturers should prioritize applying security patches promptly to prevent exploitation. The vulnerability highlights the importance of maintaining robust input validation practices and proper privilege separation within system-level components. Organizations should also consider implementing additional monitoring for unusual broadcast receiver registrations and establish proper security auditing procedures to detect potential exploitation attempts. This vulnerability demonstrates the critical need for continuous security assessment of core system components and the implementation of defense-in-depth strategies to protect against privilege escalation attacks.