CVE-2024-27837 in macOS
Summary
by MITRE • 05/14/2024
A downgrade issue was addressed with additional code-signing restrictions. This issue is fixed in macOS Sonoma 14.5. A local attacker may gain access to Keychain items.
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Analysis
by VulDB Data Team • 04/03/2026
The vulnerability identified as CVE-2024-27837 represents a significant security weakness in macOS operating systems that stems from inadequate code-signing validation mechanisms during software update processes. This downgrade issue specifically affects systems running versions prior to macOS Sonoma 14.5 where the operating system fails to properly enforce code-signing requirements when allowing software to be downgraded to older versions. The flaw creates a pathway for malicious actors to potentially exploit the system's trust model by installing modified or unauthorized software that bypasses normal security checks. The vulnerability is particularly concerning because it directly impacts the integrity of the system's security infrastructure and undermines the fundamental principle of code authentication that protects against malicious software installation.
The technical implementation of this vulnerability resides in the operating system's handling of code-signing certificates during version downgrade operations. When macOS processes a downgrade request, it should validate that all components maintain proper digital signatures from trusted authorities. However, the flaw allows for situations where older versions of software components might be installed without proper verification of their code-signing status. This creates a window of opportunity where an attacker could potentially replace legitimate system components with malicious equivalents that appear to be valid updates. The vulnerability manifests through the system's failure to maintain consistent code-signing validation across different software versions, particularly during transition periods when downgrade operations occur. This behavior directly violates the security principle of maintaining cryptographic integrity throughout the software lifecycle.
The operational impact of CVE-2024-27837 extends beyond simple code-signing validation failures to potentially enable unauthorized access to sensitive system resources. A local attacker who successfully exploits this vulnerability can gain access to Keychain items, which contain critical authentication credentials, passwords, and cryptographic keys used by the system and applications. This access represents a severe compromise of system security since Keychain items typically contain information that would normally be protected by the operating system's security mechanisms. The ability to access these items without proper authentication creates a persistent threat vector that could allow attackers to maintain access to the system, escalate privileges, or extract sensitive data. The vulnerability essentially undermines the operating system's ability to protect user credentials and system security information, making it particularly dangerous for environments where sensitive data is stored.
Security mitigations for this vulnerability require immediate system updates to macOS Sonoma 14.5 where Apple has implemented additional code-signing restrictions to address the downgrade issue. Organizations should prioritize patch management processes to ensure all affected systems receive the necessary security updates as soon as possible. System administrators should also implement monitoring solutions to detect unauthorized software installations or modifications to system components that might indicate exploitation attempts. The mitigation strategy must include verification of code-signing status for all installed software and regular audits of system integrity to ensure that no unauthorized modifications have occurred. Additionally, security teams should consider implementing additional layers of protection such as endpoint detection and response solutions that can identify suspicious behavior patterns associated with code-signing bypass attempts. This vulnerability aligns with CWE-311 and CWE-312 categories related to missing encryption and improper handling of sensitive information, and represents a technique that could be categorized under ATT&CK tactic TA0006 (Credential Access) and technique T1552.001 (Credentials In Files) in adversarial frameworks.
The resolution of CVE-2024-27837 through macOS Sonoma 14.5 demonstrates Apple's ongoing commitment to addressing security weaknesses in their operating system. The additional code-signing restrictions implemented in this update represent a more robust approach to maintaining system integrity during software operations and version transitions. Organizations should treat this vulnerability as a critical security concern requiring immediate remediation, particularly in environments where system security is paramount. The fix addresses the root cause of the downgrade issue by strengthening the validation mechanisms that ensure all software components maintain proper digital signatures regardless of version changes. This improvement in code-signing enforcement helps maintain the trust model that underpins macOS security and prevents unauthorized software from being installed with elevated privileges. The vulnerability serves as a reminder of the importance of maintaining strict code-signing validation throughout the entire software lifecycle and demonstrates how seemingly minor implementation flaws can create significant security risks.