CVE-2020-29608 in watchOS
Summary
by MITRE • 04/03/2021
An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.3, macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, iOS 14.3 and iPadOS 14.3, watchOS 7.2. A remote attacker may be able to leak memory.
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Analysis
by VulDB Data Team • 04/08/2021
This vulnerability represents a critical out-of-bounds read condition that affects multiple Apple operating systems including macOS, iOS, watchOS, and tvOS. The flaw manifests when the system processes certain inputs without proper bounds validation, potentially allowing malicious actors to access memory locations beyond the intended buffer boundaries. Such vulnerabilities are particularly dangerous because they can expose sensitive data, system internals, or cryptographic keys that should remain protected within memory space. The issue was addressed through enhanced bounds checking mechanisms that prevent unauthorized memory access patterns. The vulnerability affects versions prior to the specified security updates, with the fixes being rolled out in macOS Big Sur 11.2, Security Update 2021-001 for Catalina and Mojave, tvOS 14.3, iOS 14.3, and watchOS 7.2. This type of vulnerability falls under the Common Weakness Enumeration category CWE-129, which specifically addresses insufficient bounds checking in input validation processes. The security implications extend beyond simple data leakage, as the memory disclosure could potentially enable attackers to gather information about system internals, application state, or even sensitive cryptographic material that could be leveraged in subsequent attacks. The remote exploitation capability means that attackers do not need physical access to devices to exploit this vulnerability, making it particularly concerning for enterprise environments where devices may be exposed to untrusted networks. The fix implemented by Apple demonstrates a defensive programming approach that aligns with the principle of least privilege in memory access, ensuring that all buffer operations are validated against their declared boundaries. This vulnerability type is often categorized under the ATT&CK framework as part of the T1005 - Data from Local System technique, where adversaries attempt to extract information from compromised systems through memory access techniques.
The technical implementation of this vulnerability suggests that Apple's operating systems were processing user-supplied data or network packets without adequate validation of array indices or buffer limits. When the system encounters malformed input that exceeds expected buffer boundaries, the out-of-bounds read can result in information disclosure rather than immediate system crash. This behavior is consistent with many memory safety vulnerabilities where the primary risk is data leakage rather than denial of service. The fact that this vulnerability was patched across multiple operating system versions indicates that it affects core system components that are shared across Apple's ecosystem, suggesting a fundamental flaw in how the operating system handles certain memory operations. The memory leak characteristics of this vulnerability are particularly concerning because they can potentially reveal stack contents, heap data, or even kernel memory structures that contain sensitive information. Attackers could leverage this information to craft more sophisticated attacks, including privilege escalation attempts or targeted exploitation of other system components. The bounds checking improvements implemented by Apple likely involve runtime validation of all array accesses, ensuring that any attempt to read beyond allocated memory boundaries is prevented. This type of vulnerability is classified as a memory safety issue and is part of the broader category of buffer overflow vulnerabilities that have been the primary focus of security hardening efforts in modern operating systems. The remediation process demonstrates Apple's commitment to maintaining security across their ecosystem, as the same vulnerability was addressed in multiple product lines simultaneously, indicating a coordinated approach to vulnerability management and patch deployment.
The operational impact of this vulnerability extends beyond immediate security concerns to encompass broader enterprise security implications. Organizations that deploy Apple devices in their infrastructure must consider the potential for sensitive data exposure through this memory leak, particularly in environments where devices handle confidential information or operate in high-security zones. The remote nature of the exploit means that attackers could potentially compromise devices from external networks, making network segmentation and monitoring critical defensive measures. Security teams should prioritize patching this vulnerability across all affected systems, as the memory disclosure could provide attackers with valuable information about system configurations, application behavior, or even cryptographic implementations that could be used to target other vulnerabilities. The vulnerability's presence in multiple versions of Apple's operating systems indicates that organizations may have varying levels of exposure depending on their deployment timeline and patch management processes. This creates a complex security landscape where organizations must track and manage patches across different device types and operating system versions. The remediation process also highlights the importance of maintaining up-to-date security patches, as this vulnerability represents a known risk that has been addressed through vendor-provided updates. Organizations should implement automated patch management processes to ensure timely deployment of security updates, particularly for vulnerabilities that enable information disclosure and remote exploitation capabilities. The vulnerability's classification as a memory safety issue also underscores the importance of secure coding practices and regular security assessments of system components that handle user input or network data.