CVE-2015-3877 in Android
Summary
by MITRE
Skia, as used in Android before 5.1.1 LMY48T, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted media file, aka internal bug 20723696.
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Analysis
by VulDB Data Team • 02/03/2018
The vulnerability identified as CVE-2015-3877 represents a critical memory corruption flaw within Skia graphics library that forms a core component of Android's rendering system. This vulnerability specifically affects Android versions prior to 5.1.1 LMY48T, where the Skia graphics engine fails to properly validate input data from media files, creating an exploitable condition that can be leveraged by remote attackers. The flaw manifests through improper handling of crafted media files that contain malformed data structures, leading to unpredictable memory corruption patterns that can be exploited to execute arbitrary code or trigger denial of service conditions. The vulnerability was internally tracked as bug 20723696, indicating its recognition within Google's internal security tracking systems.
The technical implementation of this vulnerability stems from insufficient input validation within Skia's media processing routines, particularly when handling image and graphics data formats. When a maliciously crafted media file is processed by the Android system, the Skia library fails to properly bounds-check memory allocations or validate data structures, resulting in memory corruption that can be manipulated to overwrite critical memory regions. This memory corruption typically occurs during the parsing of image headers or metadata within media files, where the library assumes certain data formats without adequate validation. The flaw falls under CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds writes, both of which are common indicators of memory corruption vulnerabilities in graphics processing libraries.
The operational impact of CVE-2015-3877 extends beyond simple exploitation capabilities to encompass significant security risks for affected Android devices. Remote attackers can leverage this vulnerability through various attack vectors including malicious email attachments, web content, or media files downloaded from untrusted sources. The potential for arbitrary code execution means that compromised devices could be fully taken over, allowing attackers to install malware, steal sensitive data, or establish persistent backdoors. Additionally, the denial of service component can be used to create persistent disruptions, rendering devices unusable or causing system crashes that can be exploited for further attacks. This vulnerability directly maps to several ATT&CK techniques including T1059 for command and scripting interpreter, T1068 for exploit for privilege escalation, and T1489 for denial of service, making it a comprehensive threat vector in the attacker's toolkit.
Mitigation strategies for CVE-2015-3877 primarily focus on updating to Android 5.1.1 LMY48T or later versions where Google has implemented proper input validation and memory bounds checking within the Skia library. Organizations should prioritize immediate patching of affected devices and implement network-based protections such as content filtering to prevent malicious media files from reaching user devices. Additional protective measures include enabling automatic security updates, implementing mobile device management solutions, and conducting regular vulnerability assessments to identify any remaining unpatched systems. Security monitoring should be enhanced to detect anomalous behavior patterns that might indicate exploitation attempts, while network segmentation can help limit the potential impact if a device is compromised. The vulnerability serves as a reminder of the critical importance of proper input validation in graphics libraries and the potential consequences of memory corruption flaws in widely deployed software components.