CVE-2022-32477
📋 TL;DR
This vulnerability in Insyde InsydeH2O firmware allows DMA attacks on a shared buffer between SMM and non-SMM code, creating a TOCTOU race condition. Attackers could corrupt SMRAM and escalate privileges from user to kernel or SMM level. It affects systems with InsydeH2O kernel versions 5.0 through 5.5.
💻 Affected Systems
- Insyde InsydeH2O UEFI firmware
📦 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 with SMM-level code execution, allowing attackers to bypass all security controls, install persistent malware, and access protected memory regions.
Likely Case
Privilege escalation from user to kernel or SMM level, enabling installation of rootkits, credential theft, and persistence mechanisms.
If Mitigated
Limited impact with proper IOMMU protection and SMRAM isolation, preventing DMA attacks and buffer corruption.
🎯 Exploit Status
Exploitation requires DMA hardware access and precise timing for TOCTOU race conditions. Not trivial but feasible for skilled attackers with physical access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel version 5.6 or later
Vendor Advisory: https://www.insyde.com/security-pledge/SA-2023009
Restart Required: Yes
Instructions:
1. Check current firmware version in UEFI/BIOS settings. 2. Download updated firmware from device manufacturer's website. 3. Follow manufacturer's firmware update instructions. 4. Reboot system to apply update.
🔧 Temporary Workarounds
Enable IOMMU protection
allConfigure IOMMU to protect ACPI runtime memory used for command buffer
Enable VT-d/AMD-Vi in BIOS/UEFI settings
Configure kernel parameters: intel_iommu=on or amd_iommu=on
Restrict physical access
allPrevent unauthorized DMA-capable hardware connections
Disable Thunderbolt ports if not needed
Use BIOS/UEFI settings to disable external DMA
🧯 If You Can't Patch
- Enable IOMMU/VT-d/AMD-Vi in BIOS/UEFI settings and ensure proper kernel configuration
- Restrict physical access to systems and disable unnecessary DMA-capable ports (Thunderbolt, PCIe)
🔍 How to Verify
Check if Vulnerable:
Check UEFI/BIOS firmware version in system settings. Look for InsydeH2O kernel version 5.0-5.5.Check Version:
Windows: wmic bios get smbiosbiosversion | Linux: dmidecode -t bios | grep VersionVerify Fix Applied:
Verify firmware version is 5.6 or later in UEFI/BIOS settings. Check that IOMMU is enabled in system logs.📡 Detection & Monitoring
Log Indicators:
- Unexpected DMA operations in kernel logs
- SMM access violations
- Firmware modification attempts
Network Indicators:
- None - local attack only
SIEM Query:
Event logs showing DMA device connections or firmware access patterns