CVE-2017-0555 in Android
Summary
by MITRE
An information disclosure vulnerability in libavc 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 data without permission. Product: Android. Versions: 6.0, 6.0.1, 7.0, 7.1.1. Android ID: A-33551775.
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Analysis
by VulDB Data Team • 11/27/2022
The vulnerability identified as CVE-2017-0555 represents a critical information disclosure flaw within the libavc component of Android's Mediaserver system. This issue resides in the Android operating system's security framework where libavc serves as the access control module responsible for enforcing security policies. The vulnerability specifically affects Android versions 6.0, 6.0.1, 7.0, and 7.1.1, making it a widespread concern across multiple Android releases. The flaw allows local malicious applications to bypass normal permission boundaries and access data that should be restricted to higher privilege levels, effectively creating a privilege escalation vector.
The technical nature of this vulnerability stems from improper validation within the libavc subsystem that governs access control decisions. When Mediaserver processes media-related operations, it relies on libavc to make authorization decisions about what data a given application can access. The flaw occurs during the processing of certain media operations where the access control checks fail to properly validate the requesting application's permissions, allowing unauthorized data access. This represents a classic case of insufficient access control validation, which is categorized under CWE-284 as improper access control. The vulnerability manifests when a malicious application attempts to access media resources through the Mediaserver interface, exploiting a weakness in the permission checking mechanism that should prevent such unauthorized access.
The operational impact of this vulnerability extends beyond simple data leakage, as it fundamentally undermines the Android security model's integrity. A local malicious application can potentially access sensitive media data, including audio files, video content, and metadata that should remain protected within the system's security boundaries. This could lead to unauthorized access to personal media content, potentially including private videos, audio recordings, or other sensitive data stored on the device. The moderate severity rating reflects the fact that exploitation requires local access to the device, but the potential for data exposure remains significant. Attackers could leverage this vulnerability to gather personal information, access confidential media content, or potentially use the leaked data as a stepping stone for further exploitation. The impact is particularly concerning in environments where Android devices handle sensitive corporate or personal information.
Mitigation strategies for CVE-2017-0555 primarily focus on system updates and security hardening measures. Android users should immediately install the security patches released by Google for the affected versions, which include fixes to the libavc access control implementation. Organizations should implement comprehensive device management policies that ensure timely patch deployment and monitor for any unauthorized applications that might attempt to exploit this vulnerability. The fix typically involves strengthening the access control validation mechanisms within the Mediaserver component and ensuring proper permission checking before allowing access to protected media resources. Security professionals should also consider implementing additional monitoring for suspicious media access patterns and conduct regular security assessments to identify potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation, and represents a clear example of how access control weaknesses can compromise system integrity.