CVE-2021-33122
📋 TL;DR
This BIOS firmware vulnerability in certain Intel processors allows a privileged attacker with local access to potentially escalate privileges by exploiting insufficient control flow management. It affects systems using specific Intel processors with vulnerable BIOS firmware. The attacker must already have privileged access on the system to exploit this vulnerability.
💻 Affected Systems
- Intel processors with vulnerable BIOS firmware
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
A privileged attacker could gain higher-level system privileges, potentially compromising the entire system, accessing sensitive data, or installing persistent malware.
Likely Case
An attacker with existing administrative access could elevate privileges to gain deeper system control, potentially bypassing security controls or accessing protected resources.
If Mitigated
With proper access controls limiting administrative privileges and BIOS-level security features enabled, the attack surface is significantly reduced.
🎯 Exploit Status
Exploitation requires privileged local access and BIOS-level knowledge. No public exploit code has been reported.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: BIOS updates provided by system manufacturers
Vendor Advisory: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00601.html
Restart Required: Yes
Instructions:
1. Check system manufacturer's website for BIOS/UEFI firmware updates. 2. Download appropriate BIOS update for your system model. 3. Follow manufacturer's instructions to apply BIOS update. 4. Reboot system to complete installation.
🔧 Temporary Workarounds
Restrict administrative access
allLimit the number of users with administrative privileges to reduce attack surface
Enable BIOS/UEFI security features
allEnable secure boot, TPM, and other BIOS-level security controls
🧯 If You Can't Patch
- Implement strict access controls and least privilege principles
- Monitor for suspicious BIOS/UEFI access attempts and privilege escalation activities
🔍 How to Verify
Check if Vulnerable:
Check BIOS version against manufacturer's vulnerability list or use system information tools to identify processor and BIOS versionCheck Version:
On Windows: wmic bios get smbiosbiosversion
On Linux: sudo dmidecode -s bios-versionVerify Fix Applied:
Verify BIOS version has been updated to patched version using system BIOS/UEFI interface or manufacturer's diagnostic tools📡 Detection & Monitoring
Log Indicators:
- BIOS/UEFI firmware modification attempts
- Privilege escalation attempts from administrative users
- Unusual system-level access patterns
Network Indicators:
- Local system activity only - no network indicators
SIEM Query:
Search for BIOS/UEFI access events or privilege escalation from administrative accounts