CVE-2024-21947
📋 TL;DR
This vulnerability allows a privileged attacker to execute arbitrary code at the System Management Mode (SMM) level by exploiting improper input validation. It affects AMD processors with specific firmware versions. Attackers with local administrative access could gain persistent control over the system.
💻 Affected Systems
- AMD Ryzen processors
- AMD EPYC processors
- AMD Athlon processors with Radeon Graphics
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with persistent SMM-level malware that survives OS reinstallation and firmware updates, enabling hardware-level backdoors.
Likely Case
Privileged attackers gaining SMM-level code execution to bypass security controls, install rootkits, or maintain persistence on compromised systems.
If Mitigated
Limited to attackers with local administrative privileges; proper access controls and monitoring reduce successful exploitation.
🎯 Exploit Status
Exploitation requires deep knowledge of SMM and AMD firmware internals. No public exploits available as of current information.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware updates specified in AMD advisories SB-4012 and SB-5007
Vendor Advisory: https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-4012.html
Restart Required: Yes
Instructions:
1. Check system manufacturer's website for BIOS/UEFI firmware updates. 2. Download appropriate firmware for your specific motherboard/model. 3. Follow manufacturer's flashing instructions carefully. 4. Reboot system after update completes.
🔧 Temporary Workarounds
Restrict administrative access
allLimit local administrative privileges to trusted personnel only
Enable secure boot
allEnsure secure boot is enabled to prevent unauthorized firmware modifications
🧯 If You Can't Patch
- Isolate affected systems in high-security network segments
- Implement strict access controls and monitoring for administrative accounts
🔍 How to Verify
Check if Vulnerable:
Check BIOS/UEFI firmware version against AMD's affected version lists in SB-4012 and SB-5007 advisoriesCheck Version:
On Linux: 'sudo dmidecode -t bios' or 'sudo cat /sys/class/dmi/id/bios_version'. On Windows: 'wmic bios get smbiosbiosversion'Verify Fix Applied:
Verify firmware version has been updated to patched version specified by AMD or system manufacturer📡 Detection & Monitoring
Log Indicators:
- Unexpected firmware update attempts
- SMM-related errors in system logs
- Unauthorized BIOS/UEFI configuration changes
Network Indicators:
- Unusual outbound connections from management interfaces
- Suspicious firmware update traffic
SIEM Query:
EventID=12 OR EventID=13 (System boot/restart) combined with firmware modification events