CVE-2017-13820 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.1 is affected. The issue involves the "ATS" component. It allows remote attackers to obtain sensitive information from process memory or cause a denial of service (memory corruption) via a crafted font.
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Analysis
by VulDB Data Team • 01/21/2021
The vulnerability identified as CVE-2017-13820 resides within Apple's Apple Type Services (ATS) component, which serves as a critical font handling subsystem in macOS operating systems. This flaw affects macOS versions prior to 10.13.1 and represents a significant security weakness that could be exploited by remote attackers to gain unauthorized access to sensitive information or disrupt system operations. The ATS component is responsible for processing and rendering fonts within the operating system, making it a fundamental element that handles font-related data from various sources including network resources and user applications.
The technical nature of this vulnerability stems from improper memory handling within the ATS font processing routines, specifically when parsing crafted font files. Attackers can exploit this weakness by delivering maliciously constructed font files that trigger memory corruption issues during font rendering operations. The flaw manifests as insufficient input validation and memory management practices within the ATS subsystem, allowing attackers to either read arbitrary process memory locations or cause memory corruption that leads to system instability and potential denial of service conditions. This type of vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions where programs access memory locations outside of their intended bounds.
The operational impact of CVE-2017-13820 extends beyond simple information disclosure, as it creates multiple attack vectors that could be leveraged by threat actors. Remote attackers could potentially exploit this vulnerability through various means including malicious websites, email attachments, or file sharing protocols where font files are automatically processed. The memory corruption aspect of this vulnerability presents a particularly dangerous threat as it could enable attackers to execute arbitrary code within the context of the affected processes, potentially leading to full system compromise. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as attackers could leverage the memory corruption to inject malicious code into legitimate processes.
The exploitation of this vulnerability requires attackers to craft specific font files that trigger the memory handling flaws within ATS, making it a sophisticated attack vector that targets the operating system's core font processing capabilities. Organizations running affected macOS versions face significant risk as this vulnerability could be exploited without user interaction, making it particularly dangerous in enterprise environments where automatic font processing occurs during document rendering or web browsing activities. The vulnerability's remote exploitability means that attackers do not need physical access to target systems, enabling widespread exploitation across networked environments. Security practitioners should note that this vulnerability represents a critical threat to macOS systems and requires immediate remediation through the installation of macOS 10.13.1 or later updates that contain the necessary patches to address the ATS memory handling issues and prevent potential exploitation.