CVE-2016-3844 in Android
Summary
by MITRE
mediaserver in Android before 2016-08-05 on Nexus 9 and Pixel C devices allows attackers to gain privileges via a crafted application, aka internal bug 28299517.
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Analysis
by VulDB Data Team • 03/20/2019
The vulnerability identified as CVE-2016-3844 represents a critical privilege escalation flaw within the mediaserver component of Android operating systems. This vulnerability specifically affected Nexus 9 and Pixel C devices, which were released in 2015 and 2016 respectively, and remained unpatched until the security update released on August 5, 2016. The mediaserver process runs with elevated privileges as part of the Android multimedia framework, handling various media processing tasks including audio and video decoding, file operations, and system resource management. The flaw allowed malicious applications to exploit a weakness in the privilege management system, enabling them to execute arbitrary code with system-level privileges rather than remaining confined to their application sandbox.
The technical nature of this vulnerability stems from improper input validation and privilege handling within the mediaserver daemon. Attackers could craft specially designed applications that would trigger a specific code path within the media processing subsystem, causing the system to grant elevated permissions to the malicious application. This type of vulnerability falls under the Common Weakness Enumeration category CWE-276, which deals with improper privileges, and more specifically aligns with CWE-782, which addresses exposure of function with long lifetime but restricted scope. The flaw exploited a weakness in the Android framework's permission model where the boundary between application-level and system-level operations was improperly enforced, allowing an application to bypass normal security restrictions.
The operational impact of this vulnerability is severe and multifaceted, as it provided attackers with complete system control over affected devices. Once exploited, the malicious application could access all user data, install additional malware, modify system files, and potentially disable security features. The vulnerability was particularly dangerous because it affected devices that were considered flagship models and were widely used in enterprise and consumer environments. The attack vector required only the installation of a malicious application, which could be delivered through various means including malicious app stores, phishing campaigns, or social engineering attacks. This made the vulnerability highly exploitable and potentially widespread across the affected device base, creating significant risk for both individual users and organizations relying on these devices for business operations.
Mitigation strategies for CVE-2016-3844 centered around applying the security patch released by Google as part of their regular Android security updates. Device users were strongly advised to install the August 2016 security update immediately, which patched the privilege escalation flaw in the mediaserver component. Organizations implementing mobile device management policies should have prioritized the deployment of these security updates across their fleet of Nexus 9 and Pixel C devices. Additional protective measures included monitoring for suspicious application behavior, implementing application whitelisting policies, and ensuring that only trusted sources were used for app installation. From an ATT&CK framework perspective, this vulnerability mapped to technique T1068, which covers "Exploitation for Privilege Escalation," and could be classified under the broader category of T1059, "Command and Scripting Interpreter," as attackers could leverage the elevated privileges to execute additional malicious commands. The vulnerability also highlighted the importance of secure coding practices and proper privilege management in system-level components, emphasizing that all processes running with elevated privileges should undergo rigorous security testing and validation to prevent similar issues from occurring in the future.