CVE-2017-0837 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the Android media framework (libaudiopolicymanager). Product: Android. Versions: 5.1.1, 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0. Android ID A-64340921.
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Analysis
by VulDB Data Team • 12/12/2019
The vulnerability identified as CVE-2017-0837 represents a critical elevation of privilege flaw within the Android media framework, specifically affecting the libaudiopolicymanager component. This issue resides in the Android operating system's audio policy management system and affects multiple versions including 5.1.1, 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, and 8.0. The vulnerability stems from improper validation of audio policy configuration parameters, creating a pathway for malicious actors to escalate their privileges from standard user-level access to system-level control. This flaw operates at the kernel level within the media framework, making it particularly dangerous as it can be exploited to gain unauthorized access to sensitive system resources and functionality.
The technical implementation of this vulnerability involves a buffer overflow condition within the audio policy manager's handling of malformed audio policy configuration data. When the system processes certain audio policy parameters, the libaudiopolicymanager component fails to properly validate input boundaries, allowing attackers to craft malicious payloads that can overwrite adjacent memory regions. This memory corruption can be leveraged to execute arbitrary code with elevated privileges, effectively bypassing the standard Android security model that separates user applications from system services. The flaw is categorized under CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to privilege escalation in operating system components. The vulnerability demonstrates a weakness in the Android security model's principle of least privilege, where the audio policy manager should operate with restricted permissions but can be manipulated to gain higher privileges through carefully crafted inputs.
The operational impact of CVE-2017-0837 extends beyond simple privilege escalation, as it provides attackers with potential access to critical system functions that control audio device management and policy enforcement. This vulnerability can be exploited in various attack scenarios, including when a malicious application attempts to manipulate audio policies or when attackers leverage other initial compromise vectors to reach this privileged code path. The attack surface is particularly concerning given that audio policy management is integral to system operation and is frequently accessed by various system components. This vulnerability can be exploited through the Android application framework, where applications may attempt to modify audio policy configurations, or through more sophisticated attack chains that involve privilege escalation from a compromised application context to system-level access. The exploitation of this vulnerability can result in persistent access to device audio capabilities, potential data exfiltration through audio device manipulation, and the ability to interfere with other system services that depend on proper audio policy enforcement. This aligns with ATT&CK technique T1068, which involves the exploitation of legitimate credentials and system access for privilege escalation purposes.
Mitigation strategies for CVE-2017-0837 primarily involve applying the security patches released by Google as part of their regular Android security updates. Organizations and users should prioritize updating to Android versions that contain fixes for this vulnerability, specifically Android 8.1 and later versions where the issue has been properly addressed. The patch implements proper input validation and boundary checking within the libaudiopolicymanager component, preventing the buffer overflow conditions that enable privilege escalation. Additionally, system administrators should consider implementing additional security controls such as application sandboxing and monitoring for unusual audio policy modification attempts. The vulnerability serves as a reminder of the importance of maintaining current security patches and demonstrates how seemingly isolated components within operating systems can represent significant security risks when not properly validated. Organizations should also implement network monitoring to detect potential exploitation attempts and consider device hardening measures that limit the capabilities of applications that might attempt to manipulate audio policies. The fix addresses the root cause by implementing proper bounds checking and input validation, which aligns with security best practices outlined in the OWASP Top Ten and other industry security frameworks.