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CVE-2021-33123: escalation of privilege in Intel(R) Processors

High
VulnerabilityCVE-2021-33123cvecve-2021-33123
Published: Thu May 12 2022 (05/12/2022, 16:36:08 UTC)
Source: CVE
Vendor/Project: n/a
Product: Intel(R) Processors

Description

Improper access control in the BIOS authenticated code module for some Intel(R) Processors may allow a privileged user to potentially enable aescalation of privilege via local access.

AI-Powered Analysis

AILast updated: 07/03/2025, 10:42:09 UTC

Technical Analysis

CVE-2021-33123 is a high-severity vulnerability affecting certain Intel(R) Processors, specifically related to improper access control within the BIOS authenticated code module. This flaw allows a privileged local user to potentially escalate their privileges by exploiting weaknesses in the BIOS code authentication process. The vulnerability arises because the BIOS module does not adequately enforce access restrictions, enabling an attacker with some level of local privilege to gain higher-level control over the system. The CVSS v3.1 base score of 7.8 reflects the significant impact on confidentiality, integrity, and availability, with an attack vector limited to local access, requiring low attack complexity and privileges. No user interaction is needed, and the scope remains unchanged, meaning the exploit affects the vulnerable component without extending beyond it. While no known exploits have been reported in the wild, the vulnerability's nature makes it a critical concern for environments where local access can be obtained, such as shared workstations or multi-user systems. The BIOS is a foundational component responsible for hardware initialization and system boot processes; compromise at this level can lead to persistent, stealthy control over the affected system, bypassing many traditional security controls and potentially enabling further attacks or data exfiltration.

Potential Impact

For European organizations, this vulnerability poses a significant risk, especially in sectors where Intel processors are widely deployed in critical infrastructure, enterprise servers, and end-user devices. The ability for a local privileged user to escalate privileges can lead to unauthorized access to sensitive data, disruption of services, or installation of persistent malware at a low level, which is difficult to detect and remediate. Organizations in finance, healthcare, government, and manufacturing could face severe operational and reputational damage if attackers exploit this flaw. Additionally, environments with shared or multi-tenant systems, such as universities or co-working spaces, are particularly vulnerable. The impact is heightened by the fact that BIOS-level compromises can survive operating system reinstalls and firmware updates if not properly addressed. Given the high confidentiality, integrity, and availability impacts, exploitation could lead to data breaches, system outages, and long-term compromise of critical assets.

Mitigation Recommendations

To mitigate this vulnerability, European organizations should prioritize the following actions: 1) Apply all available firmware and BIOS updates from Intel and system vendors as soon as they are released, ensuring that the authenticated code module is patched to enforce proper access control. 2) Restrict local administrative access strictly to trusted personnel and implement robust access controls and monitoring to detect unauthorized privilege escalations. 3) Employ hardware-based security features such as Intel Boot Guard and Trusted Platform Module (TPM) to enhance BIOS integrity verification and prevent unauthorized firmware modifications. 4) Conduct regular audits of BIOS and firmware versions across the enterprise to identify and remediate vulnerable systems promptly. 5) Implement endpoint detection and response (EDR) solutions capable of detecting anomalous behavior indicative of BIOS-level compromise. 6) Educate IT staff on the risks of BIOS vulnerabilities and ensure secure configuration and update procedures are followed. These measures, combined with a strong security posture around local access controls, will reduce the risk of exploitation.

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Technical Details

Data Version
5.1
Assigner Short Name
intel
Date Reserved
2021-05-18T00:00:00.000Z
Cisa Enriched
true
Cvss Version
3.1
State
PUBLISHED

Threat ID: 682d981ec4522896dcbdbb14

Added to database: 5/21/2025, 9:08:46 AM

Last enriched: 7/3/2025, 10:42:09 AM

Last updated: 8/18/2025, 6:25:48 PM

Views: 9

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