CVE-2020-0587: Intel BIOS Privilege Escalation Flaw

CVE-2020-0587 Overview

CVE-2020-0587 is a BIOS/UEFI vulnerability affecting Intel processors that stems from improper conditions check in the BIOS firmware. This flaw may allow a privileged user with local access to potentially escalate privileges on affected systems. The vulnerability impacts a wide range of Intel processor families, including Xeon Scalable processors (Bronze, Silver, Gold, and Platinum series) and various Core i5, i7, and i9 X-series processors.

Critical Impact

A privileged local attacker could exploit this BIOS firmware weakness to escalate privileges, potentially gaining elevated control over the affected system with full confidentiality, integrity, and availability impact.

Affected Products

• Intel BIOS Firmware
• Intel Xeon Scalable Processors (Bronze 3204/3206R, Silver 4200 series, Gold 5200/6200 series, Platinum 8200/9200 series)
• Intel Core X-series Processors (i5-7640X, i7-3xxx through i7-9xxx, i9-7xxx through i9-10xxx)

Discovery Timeline

• November 12, 2020 - CVE-2020-0587 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-0587

Vulnerability Analysis

This vulnerability is classified as CWE-754 (Improper Check for Unusual or Exceptional Conditions). The flaw exists within the BIOS firmware of affected Intel processors and represents a failure to properly validate or check for specific conditions during execution. When successfully exploited, an attacker can achieve privilege escalation with complete impact on system confidentiality, integrity, and availability.

The vulnerability requires local access to the target system and high privileges, which somewhat limits the attack surface. However, once an attacker has achieved initial access with elevated privileges, they can leverage this BIOS-level flaw to gain even greater control over the system, potentially persisting below the operating system level.

Root Cause

The root cause of CVE-2020-0587 lies in the BIOS firmware's failure to properly implement condition checks for unusual or exceptional scenarios. This improper validation allows certain code paths to be executed without the expected security constraints being enforced. BIOS firmware operates at the lowest level of the system stack, meaning vulnerabilities at this layer can have far-reaching consequences that persist across operating system reinstallations.

Attack Vector

The attack vector for CVE-2020-0587 requires local access to the target system with high privileges. An attacker would need to:

1. Gain local access to a system running vulnerable Intel BIOS firmware
2. Obtain or already possess elevated privileges on the target system
3. Interact with the BIOS firmware in a manner that triggers the improper conditions check
4. Exploit the resulting security gap to escalate privileges further

This attack does not require user interaction and, if successful, can result in complete compromise of system confidentiality, integrity, and availability. The local attack vector and high privilege requirements mean this vulnerability is most likely to be exploited in scenarios where an attacker has already achieved a foothold on the system.

Detection Methods for CVE-2020-0587

Indicators of Compromise

• Unexpected BIOS/UEFI configuration changes or modifications to firmware settings
• Anomalous system behavior during boot sequences or firmware-level operations
• Evidence of unauthorized local privileged access attempts targeting BIOS interfaces
• Unexplained privilege escalation events on systems with affected Intel processors

Detection Strategies

• Monitor for unusual BIOS update attempts or firmware modification activities
• Implement hardware-based attestation to verify BIOS integrity during system boot
• Deploy endpoint detection solutions capable of monitoring pre-boot and firmware-level activities
• Utilize Intel Trusted Platform Module (TPM) measurements to detect firmware tampering

Monitoring Recommendations

• Enable BIOS event logging where supported and regularly review for anomalies
• Implement Secure Boot and monitor for any bypass attempts or configuration changes
• Track privilege escalation events on systems containing affected Intel processors
• Maintain an inventory of systems with vulnerable BIOS versions for targeted monitoring

How to Mitigate CVE-2020-0587

Immediate Actions Required

• Identify all systems in your environment using affected Intel processors and BIOS versions
• Prioritize BIOS firmware updates for critical infrastructure and high-value targets
• Apply the latest BIOS updates from your system or motherboard manufacturer
• Restrict local access to affected systems to trusted administrators only

Patch Information

Intel has released BIOS firmware updates to address CVE-2020-0587. System administrators should consult Intel Security Advisory SA-00358 for detailed information about affected products and remediation guidance. Additionally, NetApp Security Advisory NTAP-20201113-0001 provides information for affected NetApp products. BIOS updates should be obtained from the original equipment manufacturer (OEM) or motherboard vendor for the specific system in question.

Workarounds

• Restrict physical and local access to systems with vulnerable BIOS firmware
• Implement strong access controls to limit who can execute privileged operations on affected systems
• Enable BIOS password protection to prevent unauthorized firmware modifications
• Consider network segmentation to isolate systems that cannot be immediately patched

# Check current BIOS version on Linux systems
sudo dmidecode -s bios-version

# List Intel processor information to verify if system is affected
lscpu | grep -i "Model name"

# Verify Secure Boot status
mokutil --sb-state