CVE-2021-43522
📋 TL;DR
This vulnerability in Insyde InsydeH2O UEFI firmware allows attackers to write predictable data to SMRAM (System Management RAM) through a memory corruption flaw in StorageSecurityCommandDxe. Exploitation could lead to privilege escalation to System Management Mode (SMM), giving attackers high-level system control. Systems using affected InsydeH2O kernel versions 5.1-5.3 are vulnerable.
💻 Affected Systems
- Insyde InsydeH2O UEFI firmware
📦 What is this software?
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 potentially bricking hardware.
Likely Case
Local privilege escalation to SMM, enabling attackers to bypass OS security mechanisms, install persistent malware, and access sensitive system resources.
If Mitigated
Limited impact if proper firmware updates are applied and SMM protections are enabled, though residual risk remains if physical access is available.
🎯 Exploit Status
Exploitation requires local system access and knowledge of SMM memory layout. No public exploits known as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 2021-11-08 for affected kernel branches
Vendor Advisory: https://www.insyde.com/security-pledge
Restart Required: Yes
Instructions:
1. Contact device manufacturer for firmware updates. 2. Download appropriate firmware update from manufacturer website. 3. Follow manufacturer's firmware update instructions (typically via UEFI/BIOS update utility). 4. Reboot system after update.
🔧 Temporary Workarounds
Enable SMM protection features
allConfigure BIOS/UEFI settings to enable SMM protection mechanisms if available.
Restrict physical access
allLimit physical access to vulnerable systems to prevent local exploitation.
🧯 If You Can't Patch
- Isolate vulnerable systems from high-risk networks and users
- Implement strict physical security controls and monitoring
🔍 How to Verify
Check if Vulnerable:
Check firmware version in UEFI/BIOS settings or using manufacturer-specific tools; compare against affected version ranges.Check Version:
Manufacturer-specific commands vary; typically check via UEFI settings or OEM-provided system information tools.Verify Fix Applied:
Verify firmware version has been updated to post-2021-11-08 release for affected kernel branches.📡 Detection & Monitoring
Log Indicators:
- Unexpected firmware modification attempts
- SMM access violations in system logs
Network Indicators:
- Not network exploitable; focus on physical access monitoring
SIEM Query:
Search for firmware update events or unauthorized physical access to systems.🔗 References
- https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf
- https://security.netapp.com/advisory/ntap-20220216-0003/
- https://www.insyde.com/security-pledge
- https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf
- https://security.netapp.com/advisory/ntap-20220216-0003/
- https://www.insyde.com/security-pledge
- https://www.kb.cert.org/vuls/id/796611
