CVE-2022-42793 is a vulnerability in Apple's macOS operating system related to the code signature validation process. Code signing is a security mechanism that ensures the integrity and authenticity of software by verifying that an application has been signed by a trusted developer and has not been tampered with. This vulnerability allows an application to bypass these code signing checks, potentially enabling the execution of unauthorized or malicious code under the guise of a legitimate app. The issue stems from insufficient validation in the code signature verification logic, classified under CWE-347 (Improper Verification of Cryptographic Signature). Apple addressed this vulnerability by enhancing the code signature validation checks in macOS Big Sur 11.7, macOS Monterey 12.6, macOS Ventura 13, as well as iOS 15.7, iOS 16, and iPadOS 15.7. The CVSS v3.1 base score is 5.5 (medium severity), with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), unchanged scope (S:U), no confidentiality impact (C:N), high integrity impact (I:H), and no availability impact (A:N). Exploitation requires local access and user interaction, but no prior privileges, meaning an attacker could trick a user into running a malicious app that bypasses code signing protections, potentially leading to unauthorized code execution and system integrity compromise. No known exploits in the wild have been reported to date. This vulnerability is significant because code signing is a fundamental security control in macOS and iOS ecosystems, and bypassing it undermines the trust model that protects users from malicious software.

For European organizations using Apple macOS and iOS devices, this vulnerability poses a risk primarily to system integrity. An attacker with local access could exploit this flaw to run unsigned or tampered applications, potentially leading to unauthorized code execution, installation of persistent malware, or privilege escalation. This could compromise sensitive data, disrupt business operations, or facilitate further lateral movement within corporate networks. Sectors with high reliance on Apple devices, such as creative industries, finance, healthcare, and government agencies, may face increased risk. The requirement for local access and user interaction limits remote exploitation but does not eliminate risk, especially in environments where users may be targeted with social engineering or phishing attacks to run malicious apps. The lack of confidentiality and availability impact reduces the risk of data leakage or denial of service directly from this vulnerability, but the integrity compromise can have cascading effects on trustworthiness of systems and software supply chains. Organizations with Bring Your Own Device (BYOD) policies or less controlled endpoint environments are particularly vulnerable. Additionally, the vulnerability could be leveraged in targeted attacks against high-value individuals or organizations within Europe, especially if combined with other exploits or social engineering tactics.

1. Immediate deployment of Apple’s security updates for macOS Big Sur 11.7, Monterey 12.6, Ventura 13, and corresponding iOS/iPadOS versions (15.7 and 16) is critical to remediate the vulnerability. 2. Enforce strict application installation policies that restrict users from installing or running applications from untrusted sources, including disabling the ability to run unsigned apps via Gatekeeper settings. 3. Implement endpoint detection and response (EDR) solutions capable of monitoring for anomalous application behavior indicative of code signing bypass attempts. 4. Educate users on the risks of running untrusted applications and the importance of verifying application sources, especially in environments where local access is possible. 5. Employ application whitelisting where feasible to limit execution to approved software only. 6. Regularly audit and monitor macOS and iOS devices for unauthorized or suspicious applications, focusing on those that could exploit code signing bypass. 7. For organizations with BYOD policies, enforce mobile device management (MDM) solutions that can enforce compliance with security policies and patch management. 8. Consider network segmentation and least privilege principles to limit the impact of compromised endpoints. 9. Monitor threat intelligence feeds for any emerging exploits or attack campaigns leveraging this vulnerability to adjust defenses accordingly.