CVE-2022-24030: Insyde InsydeH2O Privilege Escalation Flaw

CVE-2022-24030 Overview

CVE-2022-24030 is a System Management Mode (SMM) memory corruption vulnerability in the AhciBusDxe driver of Insyde InsydeH2O firmware, affecting kernel versions 5.1 through 5.5. The flaw allows a local attacker with high privileges to write fixed or predictable data into System Management RAM (SMRAM), the protected memory region reserved for SMM execution. Successful exploitation enables privilege escalation to SMM, the most privileged execution mode on x86 platforms. Code running in SMM can bypass operating system protections, tamper with firmware, and persist below the OS. The issue is tracked under [CWE-787] (Out-of-bounds Write) and impacts multiple downstream OEMs that incorporate InsydeH2O firmware.

Critical Impact
An attacker with local privileged access can escalate to SMM, gaining ring -2 execution and the ability to bypass kernel-level security controls, Secure Boot, and OS-based endpoint protections.

Affected Products

Insyde InsydeH2O with kernel 5.1
Insyde InsydeH2O with kernel versions 5.2 through 5.4
Insyde InsydeH2O with kernel 5.5

Discovery Timeline

2022-02-03 - CVE-2022-24030 published to NVD
2025-11-04 - Last updated in NVD database

Technical Details for CVE-2022-24030

Vulnerability Analysis

The vulnerability resides in AhciBusDxe, a UEFI Driver Execution Environment (DXE) module responsible for handling Advanced Host Controller Interface (AHCI) bus operations. The driver exposes an SMM-resident handler that performs memory writes without correctly validating destination boundaries. Because the handler operates inside SMRAM, any improperly bounded write can corrupt the SMM execution context itself.

SMM runs at a higher privilege than the kernel and hypervisor. Code executing in SMM has unrestricted access to physical memory, chipset registers, and platform firmware. Successful corruption of SMRAM contents undermines the platform's root of trust and can enable persistent firmware implants that survive operating system reinstallation.

Root Cause

The root cause is an out-of-bounds write [CWE-787] inside an SMI (System Management Interrupt) handler within AhciBusDxe. Input parameters passed from a ring 0 caller into the SMM handler are not fully sanitized against SMRAM boundaries. As a result, an attacker controlling the SMI invocation can direct writes of fixed or predictable values into protected SMRAM regions.

Attack Vector

Exploitation requires local execution at a high privilege level, typically kernel or administrator. The attacker triggers a software SMI that invokes the vulnerable AhciBusDxe SMM handler with crafted parameters. The handler then writes attacker-influenced data into SMRAM, corrupting handler code paths or function pointers and yielding SMM-level code execution. Network-only and unauthenticated attacks are not feasible.

No verified public proof-of-concept code is available. Technical details are described in the Insyde Security Advisory SA-2022011 and the CERT Vulnerability Report ID 796611.

Detection Methods for CVE-2022-24030

Indicators of Compromise

Unexpected SMI activity originating from user-mode or kernel-mode processes interacting with AHCI-related I/O ports.
Firmware integrity measurements (TPM PCR values) deviating from a known-good baseline after boot.
Unsigned or modified DXE drivers detected during firmware image comparison against vendor-provided reference builds.

Detection Strategies

Compare firmware images against vendor reference hashes using tools such as CHIPSEC to identify tampered SMM modules.
Monitor for high-privilege processes issuing direct port I/O to 0xB2 (APMC) and other SMI trigger interfaces.
Audit firmware update logs and BIOS version strings to confirm systems are running patched InsydeH2O kernel revisions.

Monitoring Recommendations

Enable TPM-backed measured boot and forward PCR measurements to a central log for drift analysis.
Track BIOS/UEFI version inventory across the fleet and flag endpoints running unpatched InsydeH2O kernel 5.1 through 5.5 builds.
Correlate elevated local privilege events with subsequent firmware configuration changes or unexpected reboots.

How to Mitigate CVE-2022-24030

Immediate Actions Required

Identify all endpoints, servers, and OT devices using InsydeH2O firmware via vendor advisories from Siemens, NetApp, and OEM partners.
Apply firmware updates supplied by the OEM that incorporate Insyde's fixed kernel build addressing SA-2022011.
Restrict local administrative access and enforce least privilege to reduce the population of accounts capable of triggering the SMI handler.

Patch Information

Insyde has released fixes documented in the Insyde Security Advisory SA-2022011. Downstream vendor patches and platform-specific guidance are available in the Siemens Security Advisory SSA-306654 and the NetApp Security Advisory NTAP-20220216-0011. Apply OEM firmware updates rather than upstream Insyde packages, as integrators ship validated builds for specific hardware platforms.

Workarounds

Enable hardware-enforced features such as Intel BIOS Guard, Boot Guard, and SMM supervisor where supported by the platform.
Verify Secure Boot is enabled and configured to reject unsigned DXE modules.
Limit physical access to systems and require pre-boot authentication to reduce the risk of local privilege misuse leading to SMI abuse.

bash

# Verify InsydeH2O firmware version on Linux
sudo dmidecode -s bios-vendor
sudo dmidecode -s bios-version
sudo dmidecode -s bios-release-date

# Confirm Secure Boot status
mokutil --sb-state