CVE-2021-0091 in Intel
Summary
by MITRE • 02/10/2022
Improper access control in the firmware for some Intel(R) Processors may allow an unauthenticated user to potentially enable an escalation of privilege via local access.
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Analysis
by VulDB Data Team • 02/14/2022
This vulnerability represents a critical flaw in the firmware of certain Intel processors that undermines the fundamental security principles of access control and privilege management. The vulnerability specifically affects the firmware components that govern processor security features and access permissions, creating a pathway for unauthorized users to escalate their privileges from standard user level to administrative access. The issue stems from inadequate validation mechanisms within the firmware's privilege escalation routines, where proper authentication checks are either missing or improperly implemented, allowing local attackers with minimal access to potentially gain elevated privileges.
The technical implementation of this vulnerability involves weaknesses in the processor's firmware security architecture that govern how privilege levels are managed and validated during system operations. When a user attempts to perform privileged operations, the firmware should verify proper authorization before granting access. However, the flaw allows attackers to bypass these authorization checks through carefully crafted sequences of operations that exploit the improper access control mechanisms. This particular vulnerability is classified under CWE-284 which specifically addresses improper access control, making it a direct violation of the principle of least privilege that forms the cornerstone of secure system design. The vulnerability exists at the firmware level, meaning it operates below the operating system layer and can potentially persist across system reboots or updates, making it particularly dangerous.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a persistent backdoor that attackers can leverage to maintain long-term access to affected systems. Once an attacker successfully exploits this vulnerability, they can potentially gain access to sensitive system resources, modify critical firmware components, or establish persistent footholds within the target environment. The local access requirement means that an attacker must already have some level of access to the system, but this initial access point is often easier to obtain than attacking the system directly. This vulnerability particularly affects enterprise environments where multiple users may have local access to systems, creating potential attack vectors for insider threats or compromised accounts. The attack surface is further expanded when considering that this vulnerability affects processor-level firmware, meaning that traditional operating system-based security measures may not be sufficient to prevent exploitation.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The most critical immediate action involves applying firmware updates provided by Intel to patch the access control flaws in the affected processor implementations. Organizations should also implement strict access control policies that minimize local user privileges and regularly audit system access logs for suspicious activities that might indicate exploitation attempts. Network segmentation and monitoring solutions should be deployed to detect anomalous behavior patterns that could indicate privilege escalation attempts. The remediation process should include comprehensive testing of firmware updates to ensure compatibility and prevent system instability. Security teams should also consider implementing runtime protection mechanisms that can detect and block exploitation attempts targeting this specific vulnerability. Organizations should regularly review their privilege management policies and ensure that users only have the minimum necessary access rights to perform their legitimate functions, following the principles outlined in the mitre att&ck framework under privilege escalation techniques. The vulnerability highlights the importance of firmware security in modern computing environments where the security of hardware components directly impacts the overall system security posture.