CVE-2022-32471
📋 TL;DR
This vulnerability in InsydeH2O firmware allows attackers with local access to potentially escalate privileges or corrupt data by exploiting a time-of-check-time-of-use (TOCTOU) race condition in the IhisiSmm driver. It affects systems running InsydeH2O kernel versions 5.0 through 5.5. Attackers could modify SMRAM or OS memory after parameter validation but before use.
💻 Affected Systems
- InsydeH2O UEFI firmware with IhisiSmm driver
📦 What is this software?
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
Insydeh2o by Insyde
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via SMM privilege escalation leading to persistent firmware-level malware installation.
Likely Case
Local privilege escalation allowing attackers to gain kernel or SMM-level access from user space.
If Mitigated
Limited impact with proper access controls and firmware protections in place.
🎯 Exploit Status
Exploitation requires local access and precise timing to win the TOCTOU race condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel version 5.6 or later
Vendor Advisory: https://www.insyde.com/security-pledge/SA-2023003
Restart Required: Yes
Instructions:
1. Check with device manufacturer for firmware update availability. 2. Download and install updated firmware/BIOS from manufacturer. 3. Reboot system to apply firmware update.
🔧 Temporary Workarounds
Disable vulnerable driver
allRemove or disable IhisiDxe driver if not required for system functionality
Requires firmware configuration changes - consult manufacturer documentation
🧯 If You Can't Patch
- Implement strict local access controls and privilege separation
- Monitor for suspicious SMM-related activity and memory access patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version in UEFI/BIOS settings or using manufacturer-specific toolsCheck Version:
Manufacturer-specific commands vary - check with device OEMVerify Fix Applied:
Verify firmware version is 5.6 or later in UEFI/BIOS settings📡 Detection & Monitoring
Log Indicators:
- Unexpected SMM handler calls
- SMRAM access violations
- Firmware update failures
Network Indicators:
- None - local exploitation only
SIEM Query:
Search for firmware update events followed by system instability or privilege escalation attempts