CVE-2019-8850 in watchOS
Summary
by MITRE • 10/28/2020
An out-of-bounds read was addressed with improved input validation. This issue is fixed in macOS Catalina 10.15, iOS 13.1 and iPadOS 13.1, tvOS 13, macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006, watchOS 6. Processing a maliciously crafted audio file may disclose restricted memory.
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Analysis
by VulDB Data Team • 11/29/2020
The vulnerability identified as CVE-2019-8850 represents a critical out-of-bounds read flaw in Apple's multimedia processing stack that affects multiple operating systems including macOS, iOS, and tvOS. This issue stems from insufficient input validation mechanisms within the audio processing components that handle maliciously crafted audio files. The vulnerability is classified under CWE-125, which specifically addresses out-of-bounds read conditions where an application attempts to read memory beyond the allocated buffer boundaries. The flaw occurs during the parsing and processing of audio files, where the system fails to properly validate the structure and content of incoming audio data before attempting to access memory locations.
The technical exploitation of this vulnerability involves an attacker crafting a specially malformed audio file that, when processed by the affected systems, triggers an out-of-bounds memory read operation. This type of vulnerability falls under the ATT&CK technique T1059.007 for command and scripting interpreter and can be leveraged for information disclosure attacks. When the system attempts to parse the malicious audio file, it reads beyond the intended buffer boundaries and potentially exposes sensitive memory contents to unauthorized access. The affected components include the Core Audio framework and related audio processing services that are fundamental to media handling across Apple's ecosystem. This vulnerability demonstrates the classic pattern of insufficient boundary checking in memory management operations, where the lack of proper validation allows attackers to traverse memory regions they should not be able to access.
The operational impact of CVE-2019-8850 extends across Apple's entire consumer and enterprise product portfolio, affecting devices running the vulnerable operating system versions. The vulnerability's potential for information disclosure creates significant security implications as attackers could potentially extract sensitive data from memory, including cryptographic keys, user credentials, or application state information. This makes the vulnerability particularly dangerous in environments where devices handle confidential information or operate in security-sensitive contexts. The affected systems include iOS 13.0 and earlier versions, macOS Catalina 10.15 and earlier versions, tvOS 13.0 and earlier versions, and watchOS 6.0 and earlier versions, creating a broad attack surface across Apple's device ecosystem. The vulnerability could be exploited through various attack vectors including malicious email attachments, web downloads, or file sharing scenarios where users might unknowingly process compromised audio files.
Apple's response to this vulnerability involved implementing improved input validation mechanisms within the audio processing frameworks, specifically addressing the boundary checking deficiencies in the Core Audio components. The security updates released as part of macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006 contain patches that validate audio file structures before processing, preventing the out-of-bounds read conditions. Organizations should prioritize deployment of these security updates across all affected devices and consider implementing additional security controls such as audio file scanning, network-based intrusion detection systems, and user education about the risks of processing untrusted audio content. The vulnerability highlights the importance of robust input validation in multimedia processing components and demonstrates how seemingly benign file types can become attack vectors when proper security controls are not implemented. This flaw serves as a reminder of the critical need for comprehensive security testing of multimedia processing pipelines and the implementation of defense-in-depth strategies to protect against memory corruption vulnerabilities that could lead to information disclosure attacks.