CVE-2020-9980 in watchOS
Summary
by MITRE • 10/23/2020
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, watchOS 6.2.8. Processing a maliciously crafted font file may lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 10/04/2022
The vulnerability identified as CVE-2020-9980 represents a critical out-of-bounds write flaw that existed within Apple's font processing libraries across multiple operating systems. This issue stems from insufficient bounds checking mechanisms when handling specially crafted font files, creating a pathway for attackers to execute arbitrary code on affected systems. The vulnerability affects iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, and watchOS 6.2.8, indicating a widespread impact across Apple's ecosystem. The flaw specifically manifests during the parsing of font files, where the system fails to properly validate the boundaries of memory allocations, allowing malicious data to overwrite adjacent memory regions.
The technical implementation of this vulnerability falls under CWE-787, which describes out-of-bounds write conditions that occur when a program writes data past the end of a buffer or array. This particular issue demonstrates how font rendering engines can become attack vectors when they fail to validate input parameters properly. When a malicious font file is processed, the vulnerable code attempts to write data beyond the allocated memory boundaries, potentially overwriting critical program structures, function pointers, or return addresses. This type of memory corruption directly enables attackers to manipulate program execution flow and achieve arbitrary code execution without user interaction.
The operational impact of CVE-2020-9980 extends beyond simple exploitation as it represents a sophisticated attack surface within Apple's font handling mechanisms. Attackers could potentially deliver malicious font files through various delivery vectors including email attachments, web downloads, or compromised websites that render fonts in browsers or applications. The vulnerability's classification under the ATT&CK framework would likely map to techniques involving code injection and privilege escalation, as the successful exploitation could allow attackers to execute arbitrary commands with the privileges of the affected application. This makes the vulnerability particularly dangerous in environments where users might encounter untrusted font content.
Mitigation strategies for CVE-2020-9980 primarily focus on applying the respective security updates provided by Apple, which implement improved bounds checking mechanisms in font processing libraries. System administrators should prioritize deployment of iOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8, and watchOS 6.2.8 updates across all affected devices. Additionally, organizations should consider implementing font filtering policies that restrict the processing of untrusted font files, particularly in high-security environments. Network-level protections such as web application firewalls and content filtering systems can help prevent the delivery of malicious font files to end-user devices. The vulnerability also underscores the importance of regular security assessments and vulnerability management programs that can identify and remediate similar issues in font rendering and other input processing components across enterprise environments.