CVE-2018-6246 in Android
Summary
by MITRE
In Android before the 2018-05-05 security patch level, NVIDIA Widevine Trustlet contains a vulnerability in Widevine TA where the software reads data past the end, or before the beginning, of the intended buffer, which may lead to Information Disclosure. This issue is rated as moderate. Android: A-69383916. Reference: N-CVE-2018-6246.
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Analysis
by VulDB Data Team • 04/25/2020
The vulnerability identified as CVE-2018-6246 resides within the NVIDIA Widevine Trustlet component of Android systems, specifically affecting devices prior to the 2018-05-05 security patch level. This flaw manifests in the Widevine Trusted Application (TA) where improper buffer boundary checks allow for out-of-bounds memory access. The affected component operates within the secure execution environment of the Android platform, responsible for handling digital rights management operations for protected media content. The vulnerability represents a classic buffer overflow condition that occurs when the software attempts to read data beyond the allocated buffer boundaries, potentially exposing sensitive information stored in adjacent memory regions.
The technical nature of this vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions where software reads data past the end or before the beginning of intended buffer boundaries. This issue falls under the broader category of memory safety vulnerabilities that have long plagued mobile operating systems and embedded security components. The Widevine TA operates in a privileged execution context with access to sensitive cryptographic keys and media content, making the potential information disclosure particularly concerning. The out-of-bounds read behavior could expose memory contents including encryption keys, session tokens, or other confidential data that may be stored adjacent to the vulnerable buffer in the application's memory space.
From an operational impact perspective, this vulnerability represents a moderate risk to Android devices utilizing NVIDIA hardware components and the Widevine DRM system. Attackers who can exploit this condition may gain access to information that could be used to compromise the integrity of the digital rights management system or extract sensitive cryptographic material. The vulnerability's impact is mitigated by the fact that it requires specific conditions to be exploited effectively, typically involving manipulation of the Widevine TA input parameters. However, the nature of the flaw means that any application or service that interacts with the Widevine Trustlet could potentially provide an attack vector for information disclosure attacks.
The security implications extend beyond simple information leakage as this vulnerability could enable more sophisticated attacks when combined with other exploits within the Android security model. The Trustlet environment provides a secure execution context that should isolate sensitive operations from regular application processes, but buffer overflows in such components can undermine the security boundaries. This vulnerability demonstrates the importance of proper input validation and boundary checking in secure enclaves, particularly those handling cryptographic operations. The issue highlights the need for comprehensive security testing of trusted applications and components that operate outside the normal application sandbox.
Mitigation strategies for CVE-2018-6246 primarily involve applying the Android security patch released on 2018-05-05, which includes fixes for the buffer boundary checking issues in the Widevine Trustlet. Organizations should ensure all affected devices receive the patch promptly, as the vulnerability exists in the core system components that provide essential security services. Additionally, security monitoring should focus on identifying any unauthorized access attempts or anomalous behavior in DRM-related processes that might indicate exploitation attempts. The fix typically involves implementing proper bounds checking and input validation within the Widevine TA to prevent out-of-bounds memory access. System administrators should also consider implementing network monitoring to detect potential exploitation attempts targeting the Widevine Trustlet or related DRM services. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches in mobile environments where trusted execution components handle sensitive cryptographic operations. The issue aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage in exploitation contexts, though the primary attack vector involves memory corruption within the secure execution environment rather than traditional command injection approaches.