CVE-2022-3675 is a vulnerability identified in Fedora CoreOS related to improper input validation (CWE-20) within the GRUB bootloader password protection mechanism. Fedora CoreOS allows administrators to set a GRUB password via a Butane configuration to restrict access to the GRUB command-line interface, kernel command-line modifications, and booting of non-default OSTree deployments. However, in certain recent Fedora CoreOS releases (testing 36.20220906.2.0 and later, next 36.20220906.1.0 and later, and stable 36.20220820.3.0 and later), a misconfiguration permits booting non-default OSTree deployments without requiring the GRUB password. This flaw effectively bypasses the intended security control for booting alternate system versions. An attacker with physical or console access to the GRUB menu can exploit this to boot into an older OSTree deployment, potentially reverting the system to a state lacking recent security patches or updates. Despite this, the vulnerability does not allow modification of kernel parameters or access to the GRUB command line without authentication, limiting the scope of unauthorized changes. The vulnerability has a CVSS v3.1 base score of 2.6, indicating low severity, with an attack vector requiring physical presence (AV:P), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and a scope change (S:C). The impact is limited to integrity (I:L) without affecting confidentiality or availability. No known exploits are reported in the wild, and no patches are linked in the provided data, suggesting that remediation may require configuration adjustments or updates from Fedora Project releases. This vulnerability primarily affects systems running Fedora CoreOS with the specified versions and configurations enabling GRUB password protection for OSTree deployments.

The primary impact of CVE-2022-3675 on European organizations lies in the potential rollback of Fedora CoreOS systems to older, potentially vulnerable OSTree deployments. This rollback can negate recent security fixes, exposing systems to previously mitigated vulnerabilities and increasing the risk of compromise. The attack requires physical or console access to the machine's GRUB menu, which limits remote exploitation but raises concerns for environments with shared physical access or insufficient physical security controls. For organizations relying on Fedora CoreOS for critical infrastructure, container hosts, or edge computing nodes, this vulnerability could undermine system integrity and trustworthiness. However, since confidentiality and availability are not directly impacted, and kernel command-line modifications remain protected by password, the overall risk is constrained. The vulnerability could be exploited by insiders or attackers with temporary physical access to disrupt system security posture or facilitate further attacks by reverting to insecure system states. European organizations with strict compliance requirements or those operating in high-security sectors may face increased risk if this vulnerability is not addressed, as it could lead to non-compliance with security policies regarding system integrity and patch management.

To mitigate CVE-2022-3675, European organizations should take the following specific actions: 1) Immediately verify the Fedora CoreOS versions deployed and identify systems running the affected versions (testing 36.20220906.2.0 and later, next 36.20220906.1.0 and later, stable 36.20220820.3.0 and later). 2) Review and audit GRUB configuration files and Butane configs to ensure that the GRUB password protection is correctly enforced for all boot options, including non-default OSTree deployments. 3) Apply any available Fedora CoreOS updates or patches that address this misconfiguration as soon as they are released by the Fedora Project. 4) Enhance physical security controls to restrict unauthorized access to machines, especially those running Fedora CoreOS, to prevent attackers from reaching the GRUB menu. 5) Implement monitoring and alerting for unexpected boot events or OSTree rollbacks, using system logs and integrity verification tools to detect unauthorized boot sequences. 6) Consider disabling booting of non-default OSTree deployments if not required operationally, reducing the attack surface. 7) Educate system administrators about this vulnerability and the importance of maintaining secure boot configurations. These steps go beyond generic advice by focusing on configuration validation, physical security, and operational monitoring tailored to the nature of this vulnerability.