CVE-2023-20915 in Android
Summary
by MITRE • 01/26/2023
In addOrReplacePhoneAccount of PhoneAccountRegistrar.java, there is a possible way to enable a phone account without user interaction due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-12L Android-13Android ID: A-246930197
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Analysis
by VulDB Data Team • 09/03/2025
This vulnerability exists in the Android system's telephony framework within the PhoneAccountRegistrar.java file where the addOrReplacePhoneAccount method contains a critical logic error that allows unauthorized phone account activation without user consent. The flaw resides in the privilege validation mechanism that should require explicit user interaction to approve new phone account registrations but instead permits automatic activation through flawed conditional checks. This represents a significant security weakness that directly violates the principle of least privilege and user consent in Android's security model.
The technical implementation of this vulnerability stems from improper validation of phone account registration requests within the Android telephony subsystem. When a malicious application attempts to register a new phone account through the system's PhoneAccountRegistrar component, the logic error causes the system to bypass user approval requirements and automatically accept the registration. This occurs because the code fails to properly verify whether the requesting application has the necessary permissions or if user interaction is required for the specific type of phone account being registered. The vulnerability affects all Android versions from 10 through 13, indicating it's a long-standing issue in the platform's security architecture.
The operational impact of this vulnerability is severe as it enables local privilege escalation without requiring any additional execution privileges or user interaction. An attacker with a malicious application installed on a device can automatically register and activate phone accounts that would normally require explicit user consent, potentially allowing for unauthorized call routing, data collection, or even SIM card manipulation. This could lead to unauthorized surveillance, financial fraud through fraudulent calls, or the installation of malicious call forwarding rules that redirect communications without user knowledge. The vulnerability essentially allows attackers to silently modify the device's telephony configuration and potentially gain access to sensitive communication data.
Security implications extend beyond simple privilege escalation as this vulnerability can be exploited to create persistent backdoors within the Android telephony framework. The lack of user interaction requirement means that malicious applications can silently activate phone accounts during normal device operation, making detection extremely difficult. This vulnerability aligns with CWE-284 (Improper Access Control) and represents a failure in the Android security model's permission system. From an ATT&CK framework perspective, this maps to privilege escalation techniques and persistence mechanisms, specifically T1068 (Local Privilege Escalation) and T1546 (Event Triggered Execution). The vulnerability also demonstrates poor input validation and access control implementation, which are common attack vectors in mobile security exploits.
Mitigation strategies should focus on immediate system updates from Google that address the logic error in PhoneAccountRegistrar.java and implement proper user consent verification for all phone account registrations. Organizations should enforce strict application vetting processes and monitor for unauthorized telephony-related application installations. Device administrators should consider implementing additional security controls such as application blacklisting, network monitoring for suspicious telephony activity, and regular security audits of installed applications. Users should avoid installing applications from untrusted sources and regularly update their Android systems to ensure they have the latest security patches. The vulnerability highlights the critical importance of proper access control implementation in mobile operating systems and the need for robust user consent mechanisms in system-level operations.