CVE-2023-22614
📋 TL;DR
This vulnerability allows attackers to exploit insufficient input validation in BIOS Guard updates within InsydeH2O firmware, leading to memory corruption in System Management Mode (SMM). Attackers can execute arbitrary code with SMM privileges by supplying malformed inputs to the BIOS Guard SMI handler. Systems using Insyde InsydeH2O firmware with kernel versions 5.0 through 5.5 are affected.
💻 Affected Systems
- Insyde InsydeH2O firmware
📦 What is this software?
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SMM-level privileges allowing persistent firmware-level malware installation, bypassing OS security controls and enabling hardware-level persistence.
Likely Case
Privilege escalation to SMM level allowing attackers to bypass security controls, install persistent malware, and potentially gain full system control.
If Mitigated
Limited impact with proper firmware validation and SMM isolation controls in place, though still a serious firmware-level vulnerability.
🎯 Exploit Status
Exploitation requires local access or ability to trigger SMI handlers. Technical details and proof-of-concept are publicly available in NCC Group research.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel version 5.6 or later with security updates
Vendor Advisory: https://www.insyde.com/security-pledge/SA-2023020
Restart Required: Yes
Instructions:
1. Check with device manufacturer for BIOS/UEFI firmware updates. 2. Download appropriate firmware update from manufacturer support site. 3. Follow manufacturer instructions to flash updated firmware. 4. Reboot system to apply changes.
🔧 Temporary Workarounds
Disable BIOS Guard feature
allIf BIOS Guard functionality is not required, disable it in BIOS/UEFI settings to remove vulnerable SMI handler.
Enable SMM protection features
allEnable SMM protection mechanisms like SMM Code Access Check (SMM_CORE) if supported by hardware.
🧯 If You Can't Patch
- Implement strict physical security controls to prevent local access to vulnerable systems
- Deploy endpoint detection and response (EDR) solutions to monitor for SMM exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version using manufacturer-specific tools or UEFI/BIOS settings. Look for InsydeH2O kernel version 5.0-5.5.Check Version:
Manufacturer-specific commands vary. Common methods: dmidecode -t bios (Linux), wmic bios get smbiosbiosversion (Windows), or check BIOS/UEFI setup screen.Verify Fix Applied:
Verify firmware has been updated to kernel version 5.6 or later. Check manufacturer advisory for specific patched versions.📡 Detection & Monitoring
Log Indicators:
- Unexpected SMI handler calls
- BIOS/UEFI firmware modification events
- System management interrupt anomalies
Network Indicators:
- Local exploitation typically doesn't generate network traffic
SIEM Query:
Search for firmware modification events, SMI handler anomalies, or unexpected BIOS/UEFI access attempts in system logs.🔗 References
- https://research.nccgroup.com/2023/04/11/stepping-insyde-system-management-mode/
- https://www.insyde.com/security-pledge
- https://www.insyde.com/security-pledge/SA-2023020
- https://research.nccgroup.com/2023/04/11/stepping-insyde-system-management-mode/
- https://www.insyde.com/security-pledge
- https://www.insyde.com/security-pledge/SA-2023020
