CVE-2016-6720 in Android
Summary
by MITRE
An information disclosure vulnerability 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 2016-11-01, and 7.0 before 2016-11-01 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. Android ID: A-29422020.
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Analysis
by VulDB Data Team • 09/30/2022
The CVE-2016-6720 vulnerability represents a critical information disclosure flaw within the libstagefright library component of Android's Mediaserver service. This vulnerability exists in multiple Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, 6.x before 2016-11-01, and 7.0 before 2016-11-01, making it one of the most widespread media processing vulnerabilities in Android history. The flaw specifically affects the stagefright multimedia framework that handles media file processing and decoding, which is integral to Android's media playback functionality across various applications and system services.
The technical implementation of this vulnerability stems from improper input validation and memory handling within the libstagefright library's parsing routines. When processing specially crafted media files, the library fails to properly validate buffer boundaries and memory allocation, leading to a situation where malicious applications can manipulate memory access patterns to read data from unauthorized memory regions. This type of vulnerability maps directly to CWE-125 Uninitialized Memory Read and CWE-787 Out-of-bounds Write, both of which are common in media processing libraries where buffer overflows can occur during parsing operations. The vulnerability operates at the kernel level within the Mediaserver process, which runs with elevated privileges and can access sensitive system data that normal applications should not be able to access.
The operational impact of this vulnerability is significant as it enables local privilege escalation through information disclosure. A malicious application installed on the device can exploit this flaw to access sensitive data that would normally be restricted to system-level processes or other applications with higher permission levels. This includes potentially accessing user credentials, personal data, communication records, and other confidential information stored in memory. The vulnerability's classification as Moderate severity under CVSS scoring reflects the fact that exploitation requires a local application to be installed on the device, but the potential data exposure is substantial enough to warrant immediate attention. This vulnerability has been extensively documented in the ATT&CK framework under T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, demonstrating its potential for lateral movement and data exfiltration.
Mitigation strategies for CVE-2016-6720 require immediate system updates to patched Android versions that address the buffer overflow conditions in libstagefright. Organizations should implement comprehensive patch management policies to ensure all Android devices receive security updates promptly, particularly for enterprise-managed devices where the attack surface is larger. Additionally, network administrators should consider implementing mobile device management solutions that can automatically enforce security policies and monitor for potentially malicious applications attempting to exploit this vulnerability. The vulnerability highlights the importance of secure coding practices in media processing libraries and underscores the need for regular security audits of system components that handle untrusted input data. System administrators should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability pattern.