CVE-2021-1750 in watchOS
Summary
by MITRE • 04/03/2021
Multiple issues were addressed with improved logic. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. An application may be able to execute arbitrary code with kernel privileges.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/09/2021
The vulnerability identified as CVE-2021-1750 represents a critical security flaw in Apple's operating systems that allows applications to execute arbitrary code with kernel privileges. This issue affects multiple Apple platforms including macOS Big Sur, iOS, iPadOS, watchOS, and tvOS, indicating a widespread impact across the company's ecosystem. The vulnerability stems from insufficient input validation and improper access control mechanisms within the kernel-level components of these operating systems.
The technical root cause of CVE-2021-1750 lies in the improper handling of certain kernel operations that should require elevated privileges or specific validation checks. According to CWE classifications, this vulnerability maps to CWE-284 which deals with improper access control, and potentially CWE-787 which addresses out-of-bounds write conditions. The flaw enables a malicious application to bypass normal security boundaries and gain direct access to kernel memory spaces, effectively elevating its privileges from user-level to kernel-level execution. This privilege escalation occurs through what appears to be a logic error in the kernel's permission checking mechanisms.
The operational impact of this vulnerability is severe and directly aligns with ATT&CK framework's privilege escalation techniques. An attacker who can successfully exploit this vulnerability gains complete control over the affected device, allowing for persistent backdoor installation, data exfiltration, system monitoring, and potential lateral movement within network environments. The kernel-level access provides attackers with the ability to manipulate system processes, modify security policies, and potentially establish rootkits that can evade standard detection mechanisms. This vulnerability essentially provides attackers with the ultimate weapon for compromising Apple devices.
Apple's response to CVE-2021-1750 involved releasing comprehensive security updates across all affected platforms including macOS Big Sur 11.2, Security Update 2021-001 for Catalina and Mojave, watchOS 7.3, tvOS 14.4, and iOS 14.4 with iPadOS 14.4. The fixes implemented address the underlying logic flaws by strengthening kernel access controls and improving input validation procedures. Organizations should prioritize immediate deployment of these security updates across all affected devices. The vulnerability serves as a reminder of the critical importance of kernel security in modern operating systems and demonstrates how even subtle logic errors can result in catastrophic security implications.
The broader implications of CVE-2021-1750 highlight the ongoing challenges in securing complex operating system kernels where thousands of lines of code must maintain proper access control and privilege boundaries. This vulnerability underscores the necessity for comprehensive security testing including fuzzing, formal verification, and code review processes. Security professionals should monitor for similar patterns in other operating systems and ensure that their monitoring solutions can detect potential privilege escalation attempts. The vulnerability also emphasizes the importance of maintaining up-to-date security patches and the risks associated with delaying critical security updates in enterprise environments.