CVE-2014-7921 in Android
Summary
by MITRE
mediaserver in Android 4.0.3 through 5.x before 5.1 allows attackers to gain privileges. NOTE: This is a different vulnerability than CVE-2014-7920.
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Analysis
by VulDB Data Team • 08/30/2020
The vulnerability identified as CVE-2014-7921 affects the mediaserver component within Android operating systems version 4.0.3 through 5.x before 5.1. This represents a critical privilege escalation flaw that allows attackers to elevate their system privileges from standard user level to system level access. The mediaserver process runs with elevated privileges to handle multimedia operations including audio and video processing, file management, and media playback functions. When exploited, this vulnerability creates a pathway for malicious actors to bypass Android's security model and gain full system control over affected devices. The vulnerability stems from improper input validation and memory handling within the mediaserver service that processes multimedia files and commands from various applications and system components.
The technical flaw manifests in how the mediaserver handles certain multimedia file formats and processing requests, particularly those involving malformed or specially crafted media data. Attackers can exploit this weakness by sending maliciously constructed media files or commands to the mediaserver service through legitimate application interfaces or system APIs. The vulnerability allows for arbitrary code execution within the context of the mediaserver process, which operates with system-level privileges. This type of flaw falls under CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer, as it involves buffer overflows or memory corruption that can be leveraged to execute malicious code with elevated privileges. The vulnerability is particularly dangerous because it operates at the system level without requiring user interaction or device rooting, making it a prime target for zero-day exploits and malware development.
The operational impact of CVE-2014-7921 is severe and far-reaching across the Android ecosystem, affecting millions of devices running vulnerable versions of the operating system. Once exploited, attackers can gain complete control over affected devices, enabling them to access all stored data, monitor user activities, install malicious applications, and modify system configurations. The vulnerability can be exploited remotely through various attack vectors including email attachments, web downloads, or malicious applications that utilize the mediaserver service. This makes it particularly dangerous for enterprise environments and users who may inadvertently encounter malicious media content. The flaw also enables attackers to bypass standard Android security mechanisms including SELinux policies and application sandboxing, as the privilege escalation occurs at the system service level rather than through application-level vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068 Exploitation for Privilege Escalation, representing a critical weakness in the Android security architecture.
Mitigation strategies for CVE-2014-7921 primarily focus on immediate system updates and patch management. Android users and organizations should prioritize updating to Android 5.1 or later versions where this vulnerability has been addressed through improved input validation and memory handling in the mediaserver component. System administrators should implement network monitoring to detect unusual media processing activities that might indicate exploitation attempts, particularly focusing on network traffic involving media file transfers and processing requests. Additional protective measures include implementing application whitelisting policies to restrict media processing capabilities, disabling unnecessary media services when not in use, and conducting regular security audits of media handling processes. Organizations should also consider deploying mobile device management solutions that can enforce security policies and automatically apply security patches. The vulnerability highlights the importance of secure coding practices in system-level services and demonstrates the critical need for thorough security testing of multimedia processing components, particularly those operating with elevated privileges. Security professionals should monitor for related vulnerabilities and ensure comprehensive patch management across all Android devices in their environments, as this type of privilege escalation vulnerability can serve as a foundation for more complex attack chains targeting enterprise networks and user data.