CVE-2025-4276
📋 TL;DR
This vulnerability in UsbCoreDxe allows attackers to write arbitrary memory inside SMRAM and execute arbitrary code at SMM level, potentially bypassing all OS-level security controls. It affects systems with InsydeH2O UEFI firmware that have vulnerable USB drivers. This is a firmware-level vulnerability affecting the system's most privileged execution mode.
💻 Affected Systems
- Systems with InsydeH2O UEFI firmware
⚠️ 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 firmware-level malware that survives OS reinstallation and disk replacement, allowing attackers to bypass Secure Boot, install rootkits, and maintain persistent access.
Likely Case
Local privilege escalation to SMM level allowing attackers to disable security features, extract encryption keys, or install persistent malware that survives reboots.
If Mitigated
Limited impact if physical access controls prevent USB device connection and SMM protections are properly configured.
🎯 Exploit Status
Exploitation requires physical USB device connection or ability to manipulate USB driver stack. SMM exploitation typically requires specialized knowledge of firmware internals.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific firmware updates
Vendor Advisory: https://www.insyde.com/security-pledge/sa-2025005/
Restart Required: Yes
Instructions:
1. Check system manufacturer's website for BIOS/UEFI firmware updates. 2. Download appropriate firmware update for your system model. 3. Follow manufacturer's firmware update instructions carefully. 4. Reboot system to apply firmware update.
🔧 Temporary Workarounds
Disable unnecessary USB ports
allDisable USB ports in BIOS/UEFI settings that are not required for operation
Enable SMM protection features
allEnable SMM protection features in BIOS/UEFI settings if available
🧯 If You Can't Patch
- Restrict physical access to systems - prevent unauthorized USB device connections
- Implement USB device control policies - block unauthorized USB devices through endpoint security solutions
🔍 How to Verify
Check if Vulnerable:
Check BIOS/UEFI firmware version against vendor's patched version list. Use 'wmic bios get smbiosbiosversion' on Windows or 'dmidecode -t bios' on Linux to check current firmware version.Check Version:
Windows: wmic bios get smbiosbiosversion | Linux: sudo dmidecode -t bios | grep VersionVerify Fix Applied:
Verify firmware version has been updated to patched version. Check that SMM protections are enabled in BIOS settings.📡 Detection & Monitoring
Log Indicators:
- Unexpected firmware update attempts
- BIOS/UEFI configuration changes
- SMM-related errors in system logs
Network Indicators:
- Not network exploitable - focus on physical access monitoring
SIEM Query:
Search for: BIOS/UEFI firmware modification events, unauthorized physical access to systems, USB device policy violations