CVE-2016-0825 in Android
Summary
by MITRE
The Widevine Trusted Application in Android 6.0.1 before 2016-03-01 allows attackers to obtain sensitive TrustZone secure-storage information by leveraging kernel access, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 20860039.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2016-0825 represents a critical security flaw within the Widevine Trusted Application component of Android 6.0.1 systems, specifically prior to the 2016-03-01 security patch release. This issue resides within the TrustZone secure storage mechanisms that are designed to protect sensitive cryptographic data and access controls essential for digital rights management operations. The vulnerability stems from improper access controls within the secure execution environment, creating a pathway for malicious actors to extract confidential information stored within the trusted execution environment.
The technical implementation of this vulnerability involves an attacker with kernel-level privileges exploiting weaknesses in the Widevine Trusted Application's secure storage interfaces. The flaw specifically enables unauthorized access to signature-based access controls, allowing adversaries to obtain either Signature or SignatureOrSystem level permissions that should remain protected within the secure zone. This represents a fundamental breakdown in the isolation mechanisms that separate trusted and untrusted execution environments, as defined by the Trusted Execution Environment (TEE) standards and the GlobalPlatform TEE specifications. The vulnerability manifests through improper validation of access requests and inadequate enforcement of privilege boundaries within the secure storage subsystem.
From an operational perspective, this vulnerability poses significant risks to digital rights management systems and content protection mechanisms that rely on Android's secure execution environment. Attackers could leverage this flaw to bypass content protection measures, potentially gaining access to premium media content or proprietary software that should remain protected. The impact extends beyond simple information disclosure, as the ability to obtain SignatureOrSystem access levels could enable further privilege escalation attacks within the Android security framework. This vulnerability directly violates the principle of least privilege and demonstrates inadequate enforcement of access control policies within the TEE implementation, as outlined in the Common Weakness Enumeration (CWE) classification for improper access control.
The exploitation of this vulnerability aligns with tactics described in the MITRE ATT&CK framework under the privilege escalation and credential access domains, specifically targeting the secure storage and trusted execution environment components. Organizations implementing Android-based solutions with Widevine DRM protection face heightened risk of content piracy and unauthorized access to protected digital assets. The vulnerability also highlights the importance of proper secure storage implementation and the need for comprehensive testing of TEE components against unauthorized access attempts. Mitigation strategies should include immediate deployment of the vendor-provided security patches, implementation of additional monitoring for suspicious kernel-level activities, and review of access control policies for secure storage components. The fix typically involves strengthening the access control validation mechanisms within the Widevine Trusted Application and ensuring proper enforcement of privilege boundaries between different execution contexts.