CVE-2021-33103 is a vulnerability identified in certain Intel(R) Processors involving an unintended intermediary in the BIOS authenticated code module. This flaw allows a privileged local user to potentially escalate their privileges further on the affected system. Specifically, the vulnerability arises from the BIOS code module responsible for authenticating code execution, which contains an intermediary step that can be exploited to bypass intended privilege restrictions. The attack vector requires local access with already elevated privileges (high privileges), meaning the attacker must have some level of authorized access to the system. No user interaction is required beyond this. The vulnerability impacts confidentiality, integrity, and availability, as the attacker could gain unauthorized control over system components or sensitive data. The CVSS v3.1 base score is 6.7, categorized as medium severity, with vector metrics AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local attack vector, low attack complexity, high privileges required, no user interaction, unchanged scope, and high impact on confidentiality, integrity, and availability. There are no known exploits in the wild at the time of publication, and no specific patches or vendor advisories are linked in the provided data. The affected versions are not explicitly detailed here but are referenced elsewhere. This vulnerability is significant because BIOS-level code modules operate at a very low level in the system, and exploitation could undermine foundational security controls, potentially leading to persistent and stealthy compromise of affected systems.

For European organizations, the impact of CVE-2021-33103 could be substantial, especially for sectors relying heavily on Intel processors in critical infrastructure, government, finance, and enterprise environments. Successful exploitation could allow attackers with local privileged access to escalate their privileges further, potentially leading to full system compromise, data exfiltration, or disruption of services. This is particularly concerning for organizations with sensitive or regulated data subject to GDPR and other compliance frameworks, as breaches could result in significant legal and financial consequences. The requirement for local privileged access somewhat limits the threat to insider threats or attackers who have already compromised lower privilege accounts or systems. However, once exploited, the attacker could bypass many security controls at the BIOS level, making detection and remediation more difficult. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as threat actors may develop exploits over time. Organizations using Intel processors in their servers, workstations, and critical systems should be aware of this vulnerability and assess their exposure accordingly.

1. Apply BIOS and firmware updates from Intel or system vendors as soon as they become available to address this vulnerability. Regularly check for updates even if not explicitly linked in advisories. 2. Enforce strict access controls and monitoring on systems to limit local privileged access only to trusted administrators and processes. 3. Implement robust endpoint detection and response (EDR) solutions capable of detecting anomalous privilege escalation activities at the OS and firmware levels. 4. Use hardware-based security features such as Intel Trusted Execution Technology (TXT) and secure boot mechanisms to help ensure BIOS integrity. 5. Conduct regular security audits and penetration testing focusing on privilege escalation paths, including BIOS and firmware components. 6. Employ multi-factor authentication and least privilege principles to reduce the risk of unauthorized local access. 7. Maintain comprehensive logging and monitoring of BIOS and system firmware events where possible to detect suspicious activity early. 8. Educate system administrators and security teams about this vulnerability to increase awareness and readiness to respond to potential exploitation attempts.