CVE-2021-25501 in SecTelephonyProvider
Summary
by MITRE • 11/05/2021
An improper access control vulnerability in SCloudBnRReceiver in SecTelephonyProvider prior to SMR Nov-2021 Release 1 allows untrusted application to call some protected providers.
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Analysis
by VulDB Data Team • 11/10/2021
The vulnerability identified as CVE-2021-25501 represents a critical improper access control flaw within the SecTelephonyProvider component of the SCloudBnRReceiver subsystem. This issue affects versions prior to the SMR Nov-2021 Release 1 and fundamentally undermines the security boundaries designed to protect sensitive telephony services. The vulnerability stems from insufficient validation of application trust levels when processing incoming requests to protected telephony providers, creating an avenue for malicious actors to bypass intended security controls.
The technical implementation flaw manifests in the lack of proper authentication and authorization checks within the SCloudBnRReceiver module. When untrusted applications attempt to invoke protected telephony services through the SecTelephonyProvider interface, the system fails to adequately verify the calling application's credentials or security context. This weakness operates at the interface level where legitimate system components should enforce strict access controls while untrusted entities are appropriately denied access. The vulnerability is classified under CWE-284, which specifically addresses improper access control issues in software systems, making it a direct implementation of this well-known weakness category.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables unauthorized access to sensitive telephony functionalities that could include call routing, voicemail services, or emergency communication channels. Attackers exploiting this flaw could potentially intercept communications, manipulate call flows, or gain unauthorized access to protected telephony infrastructure. The implications are particularly severe in enterprise environments where telephony systems handle sensitive business communications or regulatory compliance requirements. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1068, which describes the exploitation of legitimate credentials or system access to gain unauthorized privileges within a system.
Mitigation strategies for CVE-2021-25501 require immediate deployment of the SMR Nov-2021 Release 1 patch which includes enhanced access control mechanisms and proper authentication checks within the SecTelephonyProvider component. Organizations should also implement network segmentation to limit access to telephony services and conduct thorough security assessments of all applications that interact with protected telephony providers. Additionally, monitoring systems should be enhanced to detect unusual access patterns to telephony services, and regular security audits should verify that proper access controls are maintained throughout the system architecture. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect core system components from unauthorized access attempts.