CVE-2017-13228 in Android
Summary
by MITRE
In function ih264d_ref_idx_reordering of libavc, there is an out-of-bounds write due to modCount being defined as an unsigned character. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: Android. Versions: 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0, 8.1. Android ID: A-69478425.
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Analysis
by VulDB Data Team • 02/03/2021
The vulnerability identified as CVE-2017-13228 represents a critical out-of-bounds write flaw within the ih264d_ref_idx_reordering function of the libavc library component used in Android systems. This issue stems from a fundamental type definition problem where modCount is declared as an unsigned character, creating a potential buffer overflow condition that can be exploited for remote code execution. The vulnerability affects multiple Android versions including 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0, and 8.1, making it a widespread concern across the Android ecosystem. The flaw resides in the video decoding process, specifically in how reference index reordering is handled during h.264 video processing, which makes it particularly dangerous as it can be triggered through multimedia content.
The technical root cause of this vulnerability can be traced to CWE-787, which describes out-of-bounds write conditions that occur when a program writes data past the end of a buffer or array. The unsigned character declaration for modCount creates a limited range of values that can be stored, typically 0-255, but when the decoding process attempts to write beyond this boundary during reference index reordering, it results in memory corruption. This memory corruption can overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical data structures. The vulnerability requires user interaction for exploitation, typically through malicious video content that triggers the affected decoding function, making it particularly concerning for mobile environments where users frequently encounter multimedia content from untrusted sources.
From an operational impact perspective, this vulnerability presents a significant risk to Android device security as it enables remote code execution without requiring additional privileges, meaning attackers can potentially compromise devices simply by delivering malicious video content. The attack vector typically involves sending specially crafted h.264 video files that, when processed by the vulnerable libavc library, trigger the out-of-bounds write condition. This could lead to complete device compromise, data theft, or installation of malicious applications. The vulnerability's presence in multiple Android versions means that a substantial portion of the Android user base remains at risk, with the potential for widespread exploitation across various device types and manufacturers.
Mitigation strategies for CVE-2017-13228 should focus on immediate patching of affected Android versions through official security updates provided by Google and device manufacturers. Organizations should implement network-level controls to filter potentially malicious multimedia content and consider mobile device management solutions that can enforce security policies and ensure timely patch deployment. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary code on affected devices. Additionally, defensive measures should include monitoring for suspicious video content delivery and implementing sandboxing mechanisms for multimedia processing to limit the potential impact of successful exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify any remaining unpatched devices within organizational networks.