CVE-2016-2485 in Android
Summary
by MITRE
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, and 6.x before 2016-06-01 does not validate OMX buffer sizes for the GSM and G711 codecs, which allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 27793367.
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Analysis
by VulDB Data Team • 01/18/2019
The vulnerability identified as CVE-2016-2485 represents a critical buffer overflow flaw within the libstagefright multimedia framework of Android operating systems. This issue affects multiple Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the specified date. The vulnerability stems from insufficient validation of OMX buffer sizes specifically for GSM and G711 codecs, creating a pathway for privilege escalation attacks. The flaw allows remote attackers to execute arbitrary code with elevated privileges, potentially gaining access to system-level permissions including Signature or SignatureOrSystem access levels.
The technical implementation of this vulnerability occurs within the mediaserver process which handles multimedia operations in Android systems. When processing media files containing crafted GSM or G711 codec data, the libstagefright library fails to properly validate buffer sizes before copying data into memory buffers. This validation failure creates a classic buffer overflow condition where attacker-controlled data can overwrite adjacent memory locations. The vulnerability specifically targets the OMX (OpenMAX) component interface used for multimedia processing, where buffer size parameters are not adequately checked against actual buffer dimensions. This allows attackers to craft malicious media files that, when processed by the affected Android versions, trigger memory corruption leading to privilege escalation.
The operational impact of CVE-2016-2485 extends beyond simple code execution as it provides attackers with elevated system privileges that can compromise the entire device. The vulnerability enables attackers to obtain Signature or SignatureOrSystem access levels, which grants them the ability to install applications with system-level permissions, modify system files, and access sensitive data. This privilege escalation capability makes the vulnerability particularly dangerous as it can be exploited remotely through various attack vectors including malicious email attachments, web downloads, or compromised applications. The vulnerability affects a wide range of Android devices and versions, making it a significant threat to mobile security across multiple Android releases.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1068, privilege escalation through exploitation of software vulnerabilities. The attack surface is particularly concerning given that the vulnerability exists within core system components that handle multimedia processing for all applications. The mediaserver process operates with elevated privileges and processes media files from untrusted sources, creating an ideal environment for exploitation. Security researchers have noted that the vulnerability can be triggered through simple media file manipulation, making it accessible to attackers with minimal technical expertise. Organizations should prioritize immediate patching of affected Android versions and implement network-level controls to prevent exploitation attempts.
Mitigation strategies for CVE-2016-2485 should include immediate deployment of official Android security patches released by Google, which address the buffer validation issues in libstagefright. System administrators should also implement application whitelisting policies to prevent execution of untrusted media files, particularly those containing GSM or G711 codecs. Network segmentation and content filtering can help reduce the attack surface by blocking potentially malicious media files from reaching vulnerable devices. Additionally, monitoring for suspicious mediaserver process behavior and implementing behavioral analytics can help detect exploitation attempts. Organizations should also consider device hardening measures including disabling unnecessary multimedia processing capabilities and implementing regular security assessments to identify potential vulnerabilities in their Android device management programs. The vulnerability underscores the importance of proper input validation in multimedia processing components and highlights the critical need for continuous security updates in mobile operating systems.