CVE-2021-1859 in macOS
Summary
by MITRE • 09/08/2021
A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3. Locked Notes content may have been unexpectedly unlocked.
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Analysis
by VulDB Data Team • 09/08/2021
This vulnerability represents a critical logic flaw in the state management mechanisms of Apple's Notes application within macOS Big Sur 11.3 operating system. The issue stems from inadequate handling of application states during locked note operations, creating a scenario where encrypted content could be accessed without proper authentication. The flaw specifically affects the notes application's ability to maintain consistent security boundaries when notes are locked and unlocked, potentially exposing sensitive data to unauthorized access.
The technical implementation of this vulnerability resides in the application's state transition management system, where the locking mechanism fails to properly enforce access controls during state changes. This represents a classic weakness in software design patterns related to proper state validation and access control enforcement. The flaw allows for a privilege escalation scenario where users could potentially bypass the intended security measures designed to protect encrypted notes. This type of vulnerability maps directly to CWE-284, which addresses improper access control, and specifically relates to weak state management within application security frameworks.
The operational impact of this vulnerability extends beyond simple data exposure risks as it undermines the fundamental security model of the Notes application. Attackers could exploit this flaw to gain unauthorized access to sensitive personal or business information stored in locked notes, potentially compromising privacy and confidentiality. The vulnerability affects all users running macOS Big Sur 11.3 who utilize the Notes application with encrypted content, creating a widespread security concern across various user demographics including enterprise customers. This weakness directly impacts the principle of least privilege and proper access control enforcement within the operating system's security architecture.
Mitigation strategies should prioritize immediate installation of the macOS Big Sur 11.3 update which addresses this specific state management issue through improved access control mechanisms. System administrators should ensure all endpoints are patched promptly and consider implementing additional monitoring for unauthorized note access patterns. Organizations may need to reassess their data protection policies and conduct thorough audits of encrypted content stored in the Notes application. The fix demonstrates proper implementation of security controls through enhanced state validation and access restriction enforcement, aligning with ATT&CK technique T1566 which covers credential harvesting and access control bypass methods. Users should also be educated about proper note locking procedures and the importance of maintaining updated system software to prevent exploitation of such logic flaws that could compromise their sensitive information.