CVE-2020-0295 in Android
Summary
by MITRE
In Telecom, there is a possible permission bypass due to an unsafe PendingIntent. This could lead to local information disclosure with User execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-155650969
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Analysis
by VulDB Data Team • 09/19/2020
The vulnerability identified as CVE-2020-0295 represents a critical permission bypass flaw within the Android telecommunications framework that exploits an unsafe PendingIntent implementation. This issue resides in the Android operating system version 11 and affects the underlying telephony services that handle incoming calls and SMS messages. The vulnerability stems from improper handling of PendingIntent objects which are used to schedule actions that occur at a later time or in response to specific events. When a malicious application attempts to exploit this weakness, it can potentially bypass intended security restrictions that should prevent unauthorized access to telephony-related functionalities.
The technical exploitation of this vulnerability occurs through the manipulation of PendingIntent objects that are used by telephony services to execute callbacks or trigger actions. An unsafe PendingIntent typically refers to a situation where the system does not properly validate the intent's target or where the PendingIntent is created without appropriate security flags. This unsafe implementation allows a malicious application to construct a PendingIntent that can execute with elevated privileges or access resources that should be restricted to system-level components. The vulnerability specifically affects the telecommunications subsystem where the system fails to properly verify the security context of incoming telephony events, creating an opportunity for privilege escalation.
From an operational perspective, this vulnerability enables local information disclosure with the requirement of user execution privileges for exploitation. While user interaction is not necessary for the attack to succeed, the malicious application must already be running with user-level privileges or have some form of legitimate access to the device. The impact of this vulnerability extends beyond simple data disclosure as it represents a potential pathway for more serious attacks including unauthorized call interception, message reading, and potentially full device compromise. The attack vector leverages the telecommunications framework's trust model where legitimate telephony services are expected to operate without additional security checks, creating a dangerous gap in the system's security architecture.
The security implications of CVE-2020-0295 align with CWE-264, which addresses permissions, privileges, and access controls, and specifically relates to improper access control mechanisms within Android's telephony services. This vulnerability also maps to ATT&CK technique T1068, which involves exploiting legitimate credentials and privileges to gain access to system resources. The flaw represents a classic case of insufficient input validation where the system fails to properly validate the security context of telephony events before executing associated PendingIntents. This weakness creates a dangerous attack surface within the Android operating system's telecommunications infrastructure, potentially allowing adversaries to exploit the trust relationships between system components to escalate privileges and access sensitive telephony data.
Mitigation strategies for this vulnerability should focus on implementing proper PendingIntent security practices including the use of FLAG_IMMUTABLE flags to prevent malicious modification of intent parameters. Android security updates should enforce stricter validation of telephony service intents and ensure that all PendingIntents used within the telecommunications framework properly validate their security context. System administrators and developers should also implement additional monitoring for suspicious telephony-related activities and ensure that applications with telephony permissions are properly vetted for security compliance. The fix typically involves updating the Android framework to properly handle PendingIntent objects within telephony services, ensuring that all security checks are performed before executing any telephony-related callbacks or actions that could potentially lead to unauthorized access or information disclosure.