CVE-2023-3567 is a use-after-free vulnerability identified in the Linux kernel's virtual console screen driver (vc_screen), specifically in the vcs_read function located in drivers/tty/vt/vc_screen.c. This flaw allows a local attacker with standard user privileges to trigger a use-after-free condition, which can lead to a kernel crash (denial of service) or potentially leak sensitive kernel memory contents. The vulnerability arises from improper handling of memory in the virtual console subsystem, where freed memory is accessed after release, causing undefined behavior. Exploitation requires local access but no elevated privileges or user interaction beyond executing code locally. The CVSS v3.1 base score is 7.1, reflecting high impact on confidentiality and availability, with low attack complexity and privileges required. While no public exploits are known, the vulnerability affects Red Hat Enterprise Linux 8 kernels and possibly other Linux distributions with similar kernel versions. The flaw could be leveraged by malicious insiders or attackers who have gained local access to escalate impact by causing system instability or extracting kernel memory data. Red Hat and the Linux community are expected to release patches to address this issue, and users should apply updates promptly to mitigate risk.

For European organizations, the impact of CVE-2023-3567 can be significant, particularly for enterprises and critical infrastructure relying on Red Hat Enterprise Linux 8. The vulnerability allows local attackers to cause system crashes, resulting in denial of service, which can disrupt business operations and services. Additionally, the potential leakage of kernel memory could expose sensitive information, undermining confidentiality and possibly aiding further attacks. Organizations with multi-user environments, such as shared servers or cloud platforms, face increased risk as any local user could exploit this flaw. The disruption of availability and confidentiality could affect sectors like finance, healthcare, government, and telecommunications, where Linux servers are prevalent. Although remote exploitation is not possible, insider threats or attackers who have compromised user accounts could leverage this vulnerability to escalate impact. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as proof-of-concept exploits may emerge. Therefore, European organizations must assess their exposure and implement mitigations swiftly to prevent potential exploitation.

To mitigate CVE-2023-3567, European organizations should: 1) Monitor Red Hat and Linux kernel advisories closely and apply official security patches as soon as they are released to eliminate the vulnerability. 2) Restrict local user access on critical systems by enforcing strict access controls and minimizing the number of users with shell or console access. 3) Employ mandatory access control mechanisms such as SELinux or AppArmor to limit the capabilities of local users and contain potential exploitation attempts. 4) Implement system integrity monitoring to detect unusual kernel crashes or memory leaks that may indicate exploitation attempts. 5) Use kernel hardening features and updated kernel versions that include security improvements to reduce the attack surface. 6) For multi-tenant or shared environments, isolate user sessions and consider containerization or virtualization to limit the impact of local exploits. 7) Educate system administrators and security teams about the vulnerability to ensure rapid response and incident handling. These steps go beyond generic advice by focusing on access restriction, monitoring, and containment specific to local kernel vulnerabilities.