CVE-2016-3751 in Android
Summary
by MITRE
Unspecified vulnerability in libpng before 1.6.20, as used 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 2016-07-01, allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 23265085.
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Analysis
by VulDB Data Team • 07/19/2024
The vulnerability identified as CVE-2016-3751 represents a critical privilege escalation flaw within the libpng library implementation across multiple Android versions. This issue affects Android operating systems from version 4.x through 6.x, specifically before the mentioned security patches were released. The vulnerability resides in the image processing capabilities of the Android framework, where the libpng library handles png image format parsing and rendering operations. Attackers can exploit this weakness by crafting malicious applications that leverage the vulnerable libpng implementation to escalate privileges within the Android security model.
The technical nature of this vulnerability stems from improper input validation and memory handling within the libpng library when processing specially crafted png image files. The flaw allows for memory corruption or manipulation that can be leveraged to bypass Android's security boundaries. According to CWE classification, this vulnerability maps to CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-125, indicating out-of-bounds read vulnerabilities. The exploit chain typically involves an attacker constructing a malicious png file that, when processed by the vulnerable libpng implementation, triggers unauthorized privilege elevation. This occurs because the image processing pipeline fails to properly validate image dimensions, color depths, or other metadata that could be manipulated to cause unexpected behavior in memory management.
The operational impact of this vulnerability is severe as it enables attackers to obtain elevated privileges within the Android system, specifically targeting Signature or SignatureOrSystem access levels. This access level allows applications to access system components and resources that should otherwise be restricted to system-level applications only. The vulnerability demonstrates how image processing libraries can serve as attack vectors for privilege escalation, with implications extending beyond simple image rendering to full system compromise. The attack surface is particularly concerning because png image files are commonly encountered in various applications, making the exploitation vector highly accessible and potentially widespread.
Security mitigations for this vulnerability require immediate patching of the affected Android versions and libpng implementations. System administrators should prioritize updating Android devices to versions that include the patched libpng library, specifically targeting Android 4.4.4, 5.0.2, 5.1.1, and 2016-07-01 releases or later. The mitigation strategy should also include network-level filtering of png image files in environments where untrusted content is processed. From an ATT&CK framework perspective, this vulnerability aligns with T1068, which covers "Exploitation for Privilege Escalation," and T1203, addressing "Exploitation of Remote Services." Organizations should implement monitoring for suspicious image processing activities and maintain updated security baselines that include regular vulnerability assessments of third-party libraries. The patching process should be comprehensive, ensuring all Android applications and system services that rely on libpng for image processing are updated to prevent exploitation attempts.