CVE-2021-43615
📋 TL;DR
This vulnerability allows attackers to write predictable data to SMRAM (System Management Mode RAM) in Insyde InsydeH2O UEFI firmware, potentially escalating privileges to SMM (System Management Mode). It affects systems with InsydeH2O kernel versions 5.1-5.5 before specific patch levels. Exploitation could lead to complete system compromise.
💻 Affected Systems
- Systems with 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 persistence, allowing attackers to bypass all OS-level security controls, install rootkits, and maintain undetectable access.
Likely Case
Privilege escalation to SMM allowing installation of persistent malware, firmware-level backdoors, or bypassing secure boot protections.
If Mitigated
Limited impact if systems are fully patched and have SMM protections enabled, though physical access could still pose risks.
🎯 Exploit Status
Requires local access and knowledge of SMM exploitation techniques. No public exploits known as of knowledge cutoff.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel 5.1: 05.16.23+, 5.2: 05.26.23+, 5.3: 05.35.23+, 5.4: 05.43.22+, 5.5: 05.51.22+
Vendor Advisory: https://www.insyde.com/security-pledge/SA-2022013
Restart Required: Yes
Instructions:
1. Contact hardware manufacturer for BIOS/UEFI firmware update. 2. Download appropriate firmware update. 3. Apply update following manufacturer instructions. 4. Reboot system. 5. Verify firmware version is updated.
🔧 Temporary Workarounds
Restrict physical access
allLimit physical access to vulnerable systems to prevent local exploitation
Enable SMM protection features
allEnable SMM protection in BIOS/UEFI settings if available
🧯 If You Can't Patch
- Isolate vulnerable systems on separate network segments
- Implement strict access controls and monitoring for systems with local administrative access
🔍 How to Verify
Check if Vulnerable:
Check BIOS/UEFI firmware version in system settings or using manufacturer-specific tools. Compare against affected version ranges.Check Version:
Manufacturer-specific commands vary. Common methods: Windows: wmic bios get smbiosbiosversion, Linux: dmidecode -s bios-versionVerify Fix Applied:
Verify firmware version shows patched version numbers after update. Check with manufacturer for specific verification tools.📡 Detection & Monitoring
Log Indicators:
- Unusual BIOS/UEFI access attempts
- SMM-related errors in system logs
- Unexpected firmware modification events
Network Indicators:
- Not network exploitable - focus on local access monitoring
SIEM Query:
Search for: BIOS/UEFI firmware modification events, SMM access attempts, or unauthorized local administrative access to vulnerable systems🔗 References
- https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf
- https://security.netapp.com/advisory/ntap-20220216-0010/
- https://www.insyde.com/security-pledge
- https://www.insyde.com/security-pledge/SA-2022013
- https://cert-portal.siemens.com/productcert/pdf/ssa-306654.pdf
- https://security.netapp.com/advisory/ntap-20220216-0010/
- https://www.insyde.com/security-pledge
- https://www.insyde.com/security-pledge/SA-2022013
- https://www.kb.cert.org/vuls/id/796611
