CVE-2020-9962 in tvOS
Summary
by MITRE • 04/03/2021
A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Big Sur 11.0.1, tvOS 14.0, macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, watchOS 7.0, iOS 14.0 and iPadOS 14.0. Processing a maliciously crafted image may lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 04/08/2021
The vulnerability identified as CVE-2020-9962 represents a critical buffer overflow condition within Apple's image processing frameworks that affects multiple operating systems including macOS Big Sur, iOS, tvOS, and watchOS. This flaw resides in the handling of maliciously crafted image files and demonstrates the classic characteristics of a buffer overflow attack vector where insufficient input validation allows attackers to write beyond allocated memory boundaries. The vulnerability is particularly concerning as it operates within the image processing subsystem that is frequently accessed by users through various applications and system components, making it a prime target for exploitation in real-world scenarios.
The technical implementation of this vulnerability stems from inadequate size validation mechanisms within Apple's image parsing libraries that are responsible for processing various image formats including jpeg, png, and other common image types. When these libraries encounter malformed image data, they fail to properly validate the buffer sizes before performing memory operations, creating opportunities for attackers to craft specially designed image files that trigger memory corruption. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-122 for heap-based buffer overflows that may occur during dynamic memory allocation processes. The flaw operates at the intersection of memory management and input validation, where the absence of proper bounds checking allows for unauthorized memory access patterns.
The operational impact of CVE-2020-9962 extends beyond simple system instability as it provides attackers with the capability to achieve arbitrary code execution on affected systems. This means that an attacker who successfully exploits this vulnerability could potentially gain complete control over the target device, execute malicious code with the privileges of the affected application, and potentially escalate privileges to system level access. The attack surface is broad since image files are commonly encountered through email attachments, web browsing, social media content, and file sharing applications, making the exploitation vector highly accessible. According to ATT&CK framework, this vulnerability would map to T1059 for command and scripting interpreter and potentially T1068 for exploit for privilege escalation, depending on the specific exploitation method used.
The remediation for this vulnerability was addressed through Apple's security updates that implemented improved size validation mechanisms within the image processing frameworks. These updates specifically targeted the memory allocation and validation routines that handle image data parsing, ensuring that all buffer operations are properly bounds-checked before execution. The affected versions include macOS Big Sur 11.0.1 and subsequent releases, iOS 14.0 and iPadOS 14.0, tvOS 14.0, and various security updates for older operating systems. Organizations should prioritize deployment of these security patches across all affected systems and implement monitoring for suspicious image file handling activities that might indicate exploitation attempts. The fix demonstrates Apple's approach to mitigating memory safety issues through improved input validation and defensive programming practices that align with industry best practices for preventing buffer overflow vulnerabilities.