CVE-2017-0381 in tvOS
Summary
by MITRE
An information disclosure vulnerability in silk/NLSF_stabilize.c in libopus in Mediaserver could enable a local malicious application to access data outside of its permission levels. This issue is rated as Moderate because it could be used to access sensitive data without permission. Product: Android. Versions: 5.0.2, 5.1.1, 6.0, 6.0.1, 7.0, 7.1. Android ID: A-31607432.
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Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-0381 represents a critical information disclosure flaw within the libopus library component of Android's Mediaserver subsystem. This issue manifests in the silk/NLSF_stabilize.c file where improper memory access controls allow local malicious applications to potentially read data beyond their designated permission boundaries. The vulnerability specifically affects Android versions 5.0.2 through 7.1, making it a widespread concern across multiple Android releases. The flaw resides in the audio processing pipeline where the Mediaserver component handles Opus audio codec operations, creating a pathway for unauthorized data access that could compromise system security and user privacy.
The technical implementation of this vulnerability stems from inadequate bounds checking and memory management within the NLSF_stabilize function, which is responsible for stabilizing the Normalized Line Spectral Frequencies used in the Opus audio compression algorithm. When processing audio data, the function fails to properly validate array indices or memory boundaries, allowing an attacker to manipulate input parameters that could cause the system to read memory locations outside the intended data structures. This type of flaw falls under CWE-129, which specifically addresses insufficient input validation, and more broadly aligns with CWE-787, representing out-of-bounds write operations that can lead to information disclosure. The vulnerability is particularly concerning because it operates at the system level within the Mediaserver process, which typically runs with elevated privileges and has access to sensitive system resources.
The operational impact of this vulnerability extends beyond simple data exposure, as it provides a potential attack vector for privilege escalation and information gathering. A malicious application with local access could exploit this flaw to extract sensitive information from adjacent memory regions, potentially including cryptographic keys, user credentials, or other confidential data. The moderate severity rating reflects the fact that exploitation requires local access and does not enable remote code execution, but the ability to bypass permission levels creates significant security implications. This vulnerability aligns with ATT&CK technique T1059.007, which covers the use of system services for privilege escalation, and T1005, covering data from local system information. The Mediaserver component's role in handling multimedia processing makes it a prime target for attackers seeking to access sensitive data without proper authorization.
Mitigation strategies for CVE-2017-0381 primarily focus on patching the affected Android versions and implementing proper memory access controls within the affected library. System administrators should ensure that all affected Android devices receive the appropriate security updates from Google, which typically include enhanced bounds checking and memory validation mechanisms. Additional protective measures include implementing application sandboxing, monitoring for anomalous memory access patterns, and conducting regular security audits of system components that handle multimedia processing. Organizations should also consider network segmentation and access controls to limit the potential impact of local exploitation, while maintaining comprehensive logging of system calls and memory operations for forensic analysis. The vulnerability demonstrates the importance of thorough input validation in system-level components and highlights the need for robust security testing of multimedia processing libraries that operate with elevated privileges.