CVE-2016-3909 in Android
Summary
by MITRE
The SoftMPEG4 component in libstagefright in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, 6.x before 2016-10-01, and 7.0 before 2016-10-01 allows attackers to gain privileges via a crafted application, aka internal bug 30033990.
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Analysis
by VulDB Data Team • 09/22/2022
The vulnerability identified as CVE-2016-3909 represents a critical privilege escalation flaw within the Android media processing framework, specifically affecting the SoftMPEG4 component in libstagefright. This vulnerability exists within the mediaserver process which handles multimedia operations across various Android versions including 4.x prior to 4.4.4, 5.0.x prior to 5.0.2, 5.1.x prior to 5.1.1, 6.x prior to October 1, 2016, and 7.0 prior to the same date. The flaw allows malicious applications to exploit the media processing pipeline and elevate their privileges to the system level, effectively bypassing Android's security model and gaining unauthorized access to sensitive system resources.
The technical root cause of this vulnerability lies in improper input validation and memory handling within the stagefright media framework's MPEG4 parsing implementation. When processing crafted media files, the SoftMPEG4 component fails to properly validate buffer boundaries and memory allocations, creating opportunities for attackers to manipulate memory structures and execute arbitrary code with elevated privileges. This type of vulnerability falls under CWE-121, which describes "Stack-based Buffer Overflow" and CWE-787, "Out-of-bounds Write," as attackers can leverage buffer overflows to overwrite critical memory locations including return addresses and function pointers within the execution context of the mediaserver process.
The operational impact of this vulnerability is severe as it enables attackers to achieve system-level privilege escalation without requiring physical access or user interaction. Once exploited, compromised applications can read/write arbitrary files, execute code with system privileges, modify system configurations, and potentially access sensitive user data including personal information, credentials, and encrypted communications. This vulnerability directly maps to ATT&CK technique T1068, "Exploitation for Privilege Escalation," and T1059, "Command and Scripting Interpreter," as it allows attackers to leverage existing applications to gain elevated system access and execute malicious code within the system context.
The attack surface for this vulnerability is particularly concerning as it affects core Android system components that are frequently utilized for media processing across various applications and services. The mediaserver process runs with system-level privileges and handles multimedia files from multiple sources, making it an attractive target for exploitation. The vulnerability's persistence across multiple Android versions indicates a fundamental flaw in the media processing pipeline that required coordinated patches across different Android releases to address the underlying memory handling and input validation issues. Organizations should implement immediate mitigations including applying security patches, monitoring for suspicious media processing activities, and restricting media file handling from untrusted sources to prevent exploitation of this privilege escalation vulnerability.
This vulnerability demonstrates the critical importance of secure memory management in system-level components and highlights the potential for seemingly benign media processing functionality to become a vector for system compromise. The exploitation of such vulnerabilities underscores the necessity of robust input validation, proper memory boundary checking, and comprehensive security testing of core system frameworks to prevent attackers from leveraging media processing pipelines for unauthorized privilege escalation and system compromise.