CVE-2020-29633 in macOS
Summary
by MITRE • 04/03/2021
An authentication issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave. An attacker in a privileged network position may be able to bypass authentication policy.
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Analysis
by VulDB Data Team • 05/08/2026
This authentication vulnerability represents a critical weakness in macOS security architecture that stems from inadequate state management during authentication processes. The flaw allows attackers positioned within a privileged network environment to circumvent established authentication policies, effectively undermining the operating system's security controls. The vulnerability affects multiple macOS versions including Big Sur 11.1 and 11.2, as well as various Security Update releases for Catalina and Mojave, indicating a widespread issue that required coordinated patching across the macOS ecosystem. The root cause lies in how the system manages authentication state transitions, creating potential pathways for unauthorized access when network traffic can be intercepted or manipulated by malicious actors. This type of vulnerability falls under the CWE-284 category for improper access control, specifically addressing weaknesses in authentication mechanisms that allow privilege escalation or unauthorized system access.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables attackers to bypass authentication policies entirely rather than merely exploiting weak credentials. An attacker in a privileged network position could potentially manipulate authentication state variables to gain unauthorized access to system resources, user accounts, or administrative functions. The vulnerability's exploitation requires network-level access and understanding of the authentication flow, making it particularly dangerous in environments where attackers have already established a foothold within the network infrastructure. This scenario aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, as the flaw enables attackers to leverage legitimate authentication mechanisms in unintended ways. The security implications are significant for enterprise environments where macOS devices may be exposed to untrusted network segments or where network monitoring capabilities are insufficient to detect such state manipulation attacks.
The remediation efforts required for this vulnerability demonstrate the complexity of authentication system design and the importance of proper state management in security-critical applications. Apple's response through targeted security updates for specific macOS versions shows the need for precise patching to address authentication state issues without disrupting legitimate user workflows. Organizations should prioritize deployment of these security updates across all affected macOS systems, particularly in environments where network segmentation is not sufficient to isolate privileged network positions. The vulnerability highlights the importance of implementing additional security controls such as network access controls, monitoring for unusual authentication patterns, and regular security assessments of authentication mechanisms. Security teams should also consider implementing multi-factor authentication as a compensating control, given that this vulnerability specifically targets the authentication state management rather than the underlying credential storage or transmission mechanisms. The fix emphasizes the critical nature of maintaining proper session state management and ensuring that authentication policies are enforced at multiple layers of the security architecture to prevent exploitation by attackers who can manipulate network-level authentication flows.