CVE-2023-22616 – This vulnerability in Insyde InsydeH2O UEFI fir... (How to Fix)

Q: What is the severity of CVE-2023-22616?

CVE-2023-22616 has a CVSS score of 7.8 (HIGH). This vulnerability in Insyde InsydeH2O UEFI firmware allows attackers to corrupt System Management RAM (SMRAM) due to insufficient validation of save state register values. Attackers with local access can potentially execute arbitrary code in System Management Mode, compromising the entire system. This affects systems with InsydeH2O kernel versions 5.2 through 5.5.

📋 TL;DR

This vulnerability in Insyde InsydeH2O UEFI firmware allows attackers to corrupt System Management RAM (SMRAM) due to insufficient validation of save state register values. Attackers with local access can potentially execute arbitrary code in System Management Mode, compromising the entire system. This affects systems with InsydeH2O kernel versions 5.2 through 5.5.

💻 Affected Systems

Products:

Systems with Insyde InsydeH2O UEFI firmware

Versions: Kernel versions 5.2 through 5.5

Operating Systems: All operating systems running on affected hardware

Default Config Vulnerable: ⚠️ Yes

Notes: Affects various OEM devices using InsydeH2O firmware; check with hardware manufacturer for specific device models.

📦 What is this software?

Insydeh2o by Insyde

View all CVEs affecting Insydeh2o →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise via arbitrary code execution in System Management Mode, allowing persistent firmware-level malware installation that survives OS reinstallation.

🟠

Likely Case

Local privilege escalation to kernel or system-level access, enabling data theft, persistence mechanisms, or disabling security controls.

🟢

If Mitigated

Limited impact if proper access controls prevent local attacker access and firmware updates are applied promptly.

🌐 Internet-Facing: LOW - Requires local system access for exploitation, not directly exploitable over network.

🏢 Internal Only: HIGH - Malicious insiders or compromised accounts with local access can exploit this for significant privilege escalation.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and knowledge of SMM exploitation techniques; technical details and proof-of-concept are publicly available in NCC Group research.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check with hardware/OEM vendor for specific firmware updates

Vendor Advisory: https://www.insyde.com/security-pledge/SA-2023022

Restart Required: Yes

Instructions:

1. Contact hardware manufacturer for firmware updates. 2. Download appropriate firmware update from manufacturer website. 3. Follow manufacturer's firmware update procedure. 4. Reboot system to apply update.

🔧 Temporary Workarounds

Restrict local access

all

Limit physical and administrative access to vulnerable systems to trusted personnel only

Enable secure boot

all

Ensure UEFI Secure Boot is enabled to prevent unauthorized firmware modifications

🧯 If You Can't Patch

Isolate affected systems on separate network segments
Implement strict access controls and monitoring for systems with local administrative access

🔍 How to Verify

Check if Vulnerable:

Check UEFI firmware version in BIOS/UEFI settings or using manufacturer-specific tools; look for InsydeH2O kernel version 5.2-5.5

Check Version:

Manufacturer-specific commands vary; typically check BIOS/UEFI settings or use 'dmidecode' on Linux or 'wmic bios get smbiosbiosversion' on Windows

Verify Fix Applied:

Verify firmware version has been updated to a version beyond affected range per manufacturer documentation

📡 Detection & Monitoring

Log Indicators:

Unexpected firmware update attempts
SMM-related errors in system logs
Unauthorized BIOS/UEFI configuration changes

Network Indicators:

Unusual outbound connections from firmware management interfaces

SIEM Query:

EventID=12 OR EventID=13 (System startup/shutdown) combined with firmware modification alerts

📊 Metadata

CVE ID: CVE-2023-22616

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-610

Published: April 12, 2023

Last Updated: February 10, 2025

🔗 References

https://research.nccgroup.com/2023/04/11/stepping-insyde-system-management-mode/ Exploit,Third Party Advisory
https://www.insyde.com/security-pledge Vendor Advisory
https://www.insyde.com/security-pledge/SA-2023022 Vendor Advisory
https://research.nccgroup.com/2023/04/11/stepping-insyde-system-management-mode/ Exploit,Third Party Advisory
https://www.insyde.com/security-pledge Vendor Advisory
https://www.insyde.com/security-pledge/SA-2023022 Vendor Advisory

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