CVE-2018-6336 is a high-severity vulnerability affecting Facebook's osquery software prior to version 3.2.7. Osquery is an open-source tool that enables querying of operating system data using SQL-like queries, widely used for endpoint monitoring and security analytics. The vulnerability arises from improper handling of Universal/fat binaries on macOS systems. Specifically, a maliciously crafted Universal/fat binary can evade third-party code signing verification processes. These binaries contain multiple architectures within a single file. The flaw is that third-party tools performing code signing checks do not fully inspect all architectures within the binary. As a result, the user or security tool may incorrectly assume the entire binary is signed by Apple, while malicious unsigned code embedded in one architecture slice executes undetected. This bypasses code signing protections designed to ensure only trusted, signed code runs on macOS. The vulnerability is classified under CWE-254 (Security Features), indicating a failure in security mechanisms. The CVSS 3.1 base score is 7.8 (high), with attack vector local, low attack complexity, no privileges required, user interaction required, unchanged scope, and high impact on confidentiality, integrity, and availability. Although exploitation requires local access and user interaction, the impact is severe because it allows execution of unsigned malicious code under the guise of a trusted Apple-signed binary. No known exploits in the wild have been reported. The issue was addressed in osquery version 3.2.7, which presumably includes improved binary inspection and validation to prevent this evasion technique.

For European organizations, the impact of this vulnerability can be significant, especially those relying on osquery for endpoint security monitoring and compliance on macOS devices. Successful exploitation allows attackers to execute unsigned malicious code while bypassing code signing protections, potentially leading to unauthorized data access, system compromise, and disruption of critical services. This undermines the integrity and trustworthiness of security monitoring tools, possibly allowing attackers to evade detection and persist on endpoints. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, face increased risks of data breaches and regulatory non-compliance. Additionally, the need for local access and user interaction means insider threats or social engineering attacks could leverage this vulnerability to escalate privileges or implant persistent malware. The high confidentiality, integrity, and availability impacts highlight the potential for severe operational and reputational damage if exploited.

European organizations should ensure all macOS endpoints running osquery are updated to version 3.2.7 or later, where this vulnerability is patched. Beyond patching, organizations should implement strict application whitelisting and endpoint protection controls to detect and block execution of unsigned or suspicious binaries. Security teams should audit and monitor code signing verification processes within third-party tools to confirm they fully inspect all architectures in Universal/fat binaries. User education to reduce the risk of social engineering and inadvertent execution of malicious binaries is critical. Employing macOS native security features such as System Integrity Protection (SIP) and Gatekeeper can provide additional layers of defense. Regularly reviewing and restricting local user privileges can limit the ability of attackers to exploit local vulnerabilities requiring user interaction. Finally, integrating osquery logs with centralized SIEM solutions can help detect anomalous behavior indicative of exploitation attempts.