CVE-2024-9407 is a medium-severity vulnerability affecting the Docker build process, specifically the bind-propagation option of the RUN --mount instruction in Dockerfiles. This vulnerability arises due to improper input validation, allowing an attacker with sufficient privileges to pass arbitrary parameters to the mount instruction during container image builds. Exploiting this flaw enables mounting sensitive directories from the host system into the container build environment. Consequently, an attacker can gain unauthorized access to host files and, in some cases, modify the contents of these files. Notably, this vulnerability can bypass SELinux protections by relabeling the source directory, thereby granting the container access to host files that would otherwise be restricted. The vulnerability requires local access with high privileges (PR:H) and does not require user interaction (UI:N). The attack vector is local (AV:L), and the complexity is high (AC:H), indicating that exploitation is non-trivial and requires elevated permissions on the host. The impact on confidentiality is high due to potential exposure of sensitive host files, integrity impact is low as modification is possible but limited, and availability is not affected. No known exploits are currently reported in the wild, and no patches or mitigations have been explicitly linked yet. This vulnerability primarily affects environments where Docker is used for container builds, especially where untrusted users have the ability to execute Docker build commands or where build environments are shared or multi-tenant.

For European organizations, the impact of CVE-2024-9407 can be significant in environments relying heavily on containerization and Docker-based build pipelines. Organizations in sectors such as finance, healthcare, manufacturing, and critical infrastructure that use Docker for continuous integration and deployment (CI/CD) could face confidentiality breaches if attackers exploit this vulnerability to access sensitive host files. The ability to bypass SELinux protections exacerbates the risk, particularly in organizations that rely on SELinux for mandatory access control. Unauthorized access to host files could lead to leakage of intellectual property, customer data, or internal configuration files, potentially resulting in regulatory non-compliance under GDPR and other data protection laws. Although the vulnerability requires high privileges and local access, insider threats or compromised build systems could leverage this flaw to escalate access or move laterally within the network. The lack of known exploits in the wild suggests limited immediate risk, but the potential for future exploitation necessitates proactive mitigation. The medium CVSS score reflects the balance between the difficulty of exploitation and the severity of impact on confidentiality.

To mitigate CVE-2024-9407, European organizations should implement several specific measures beyond generic Docker security best practices: 1) Restrict Docker build capabilities to trusted users only, ensuring that only administrators or highly trusted personnel can execute Docker builds with RUN --mount instructions. 2) Employ strict access controls and auditing on build servers to detect and prevent unauthorized build commands that could exploit this vulnerability. 3) Use container build isolation techniques such as dedicated build nodes or sandboxed environments that limit the potential damage from malicious mount instructions. 4) Monitor SELinux policies and logs for unusual relabeling activities that could indicate attempts to bypass protections. 5) Regularly update Docker to the latest versions once patches addressing this vulnerability are released, and subscribe to vendor advisories for timely patch deployment. 6) Consider implementing additional host-level security controls such as Mandatory Access Control (MAC) frameworks beyond SELinux or AppArmor to provide layered defense. 7) Review and harden Dockerfile practices by avoiding unnecessary use of bind-propagation options and validating inputs in build scripts. 8) Conduct internal security assessments and penetration testing focused on container build environments to identify potential exploitation paths.