CVE-2017-13275 in Android
Summary
by MITRE
In getVSCoverage of CmapCoverage.cpp, there is a possible out of bounds read due to an incorrect bounds check. This could lead to local information disclosure with no additional privileges needed. User interaction is needed for exploitation. Product: Android. Versions: 8.0, 8.1. Android ID: A-70808908.
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Analysis
by VulDB Data Team • 01/21/2020
The vulnerability identified as CVE-2017-13275 represents a critical out-of-bounds read flaw within the font handling subsystem of Android 8.0 and 8.1 operating systems. This issue resides in the getVSCoverage function located within the CmapCoverage.cpp source file, which is part of the Android framework's font rendering capabilities. The flaw stems from an inadequate bounds checking mechanism that fails to properly validate array access boundaries during font coverage processing operations.
The technical nature of this vulnerability manifests as a memory access violation where the application attempts to read data beyond the allocated memory boundaries of font coverage arrays. This improper bounds validation creates a scenario where maliciously crafted font files could trigger the out-of-bounds read condition, potentially exposing sensitive memory contents to unauthorized access. The vulnerability requires user interaction for exploitation, typically through the presentation of a specially crafted font file that triggers the vulnerable code path during font processing operations. This interaction requirement aligns with attack patterns described in the ATT&CK framework under the T1059.007 technique for process injection and T1203 for exploitation for execution.
From an operational impact perspective, this vulnerability enables local information disclosure without requiring any special privileges or root access, making it particularly concerning for mobile environments where users frequently interact with various font resources. The exposure of memory contents could potentially reveal sensitive information including cryptographic keys, user credentials, or application memory structures that could be leveraged for further attacks. The vulnerability affects the core font rendering functionality of Android systems, which means any application that processes or displays text using fonts could potentially be exploited, creating a broad attack surface that extends across multiple applications and system components.
The mitigation strategies for this vulnerability should focus on immediate patch deployment through Android security updates, as well as implementing additional runtime protections such as memory corruption detection mechanisms and enhanced input validation for font processing operations. Organizations should also consider implementing application whitelisting policies that restrict font file processing to trusted sources only. The vulnerability demonstrates the importance of proper bounds checking in memory management operations and aligns with CWE-129 which addresses improper bounds checking in software development practices. This issue underscores the critical need for robust input validation and memory safety mechanisms in mobile operating systems where font rendering is a fundamental component of user interface functionality.