CVE-2022-24030

Executive Summary

CVE-2022-24030 is an SMM memory corruption vulnerability in the AhciBusDxe module of the Insyde InsydeH2O firmware, affecting system firmware based on kernels 5.1 through 5.5. A local attacker with adequate privileges could exploit this flaw to write attacker-controllable fixed or predictable data to System Management Memory (SMRAM), thereby achieving arbitrary code execution at the most privileged x86 execution mode — System Management Mode (SMM). Successful exploitation results in a complete loss of confidentiality, integrity, and availability from any higher software layer, enabling firmware-level persistence, UEFI Secure Boot bypass, and hypervisor subversion on affected client and server platforms.

Technical Analysis

The vulnerability resides in the AhciBusDxe driver — a UEFI driver responsible for managing AHCI (Advanced Host Controller Interface) storage devices within the DXE (Driver Execution Environment) phase of the firmware boot process. The affected component operates within the SMM (System Management Mode) context, where SMRAM (System Management RAM) is a protected memory region that is inaccessible to the OS and hypervisor.

Vulnerability class: CWE-787 (Out-of-bounds Write). The flaw is an SMM memory corruption bug that permits an attacker to write fixed or predictable data to a target location in SMRAM. The qualifier "fixed or predictable data" is significant — unlike a typical arbitrary-write primitive, this vulnerability gives the attacker deterministic control over the content being written (e.g., a constant value, a zero, or a known offset), possibly without full address-arbitrary write capability. However, when combined with pointer redirection or carefully chosen target addresses, even a fixed write can corrupt key SMM data structures, return addresses, or function pointers to redirect execution flow into attacker-placed code.

Attack surface:

• The attack surface is local only (CVSS AV:L). The attacker requires High privileges (PR:H) to trigger the vulnerable code path, and the attack complexity is High (AC:H) — it likely requires precise race-condition control or specific OS/driver-interface calls to influence SMM heap layout, SMM communication buffer contents, or arbitration logic in the SMI handler.
• The attack is performed with no user interaction (UI:N) and produces a scope change (S:C) — the compromise transitions from the OS/ring-0 level into SMM (below the hypervisor, below firmware).

Technical mechanism (at vulnerability-class level): The set of possible triggers is not fully described in the public advisory. Based on the affected module and the write primitive described, exploitation likely involves: (1) an SMI (System Management Interrupt) handler in AhciBusDxe that receives data from a non-SMM source (e.g., a communication buffer in ACPI/Reserved memory), (2) a lack of bounds checking when copying or processing AHCI command table entries, command descriptors, or vendor-specific AHCI registers, causing a write past the intended SMRAM buffer, and (3) the attacker having sufficient control over OS-level I/O port or MMIO interactions (e.g., via a kernel driver or a compromised SMM callout) to both direct the corrupting write to a useful target and to control enough of the neighboring SM RAM address space to place a subsequent malicious payload or to manipulate an SMM function pointer. The exploitation is further complicated by SMRAM being marked read-only after SMM initialization — the attacker must typically win a race to write to SMRAM before page protection is locked (e.g., during SMM entry) or use a write primitive that bypasses existing protections (an SMI handler that writes directly without CR0.WP protection checks).

The vulnerability's class ("SMM memory corruption") is a well-known rootkit target: because SMM executes with privileges higher than ring-0, exploiting this flaw would allow the attacker to hide processes, install a bootkit at the firmware level, reprogram SPI flash for persistence, and intercept all system memory — including the hypervisor.

Exploitation Scenarios

Vendor/description detail is sparse; the attack chain below is inferred at the vulnerability-class level. No public exploit code exists.

Step 1 — Reconnaissance / Target Identification

• An attacker who already holds elevated privileges (e.g., a ring-0 kernel driver, or a compromised OEM-supplied service) must first identify the target machine's firmware version. This is typically done by reading the SMBIOS/UEFI firmware version (e.g., GetSystemFirmwareTable or SMBIOS table) and confirming InsydeH2O with kernel 5.1–5.5 is present.
• The attacker must map the SMM communication interface exposed by the AhciBusDxe driver. In practice, this involves locating SMM communication protocol GUIDs (e.g., EFI_SMM_COMMUNICATION_PROTOCOL) in UEFI protocol database, and probing the communication buffer structure.

Step 2 — Trigger of the Flaw Class

• Exploitation requires triggering a vulnerable SMI handler. A common pattern for such drivers is that the SMI handler receives data from a shared communication buffer residing in regular memory. The attacker populates this buffer with a crafted AHCI command structure (e.g., a Command List Entry, a Physical Region Descriptor Table, or a port register write request that references an out-of-range index).
• The attacker writes a value (e.g., a fixed constant like 0, 0xFFFFFFFF, or an offset) to a field that the driver will subsequently write into SMRAM without proper bounds validation — the "fixed or predictable data write" primitive.

Step 3 — Payload / Execution Method (vulnerability-class level)

• Because the corruption is constrained to fixed or predictable data, the attacker must orient the write to land on a critical SMM data structure:
  • A SMM function pointer table (e.g., SmmDispatchedProtocol or a handler dispatch table) — overwriting one entry to point at an SMRAM-resident attacker-planted payload.
  • A SMM heap metadata header — enabling arbitrary code execution via heap manipulation.
  • The SMM Save State area — to hijack control flow on SMM return.
• Without a public PoC or more detail, the exact overwritten target is unknown. A plausible chain involves: (a) planting shellcode in SMRAM via a prior SMM communication call or NVRAM variable, (b) triggering the write to corrupt a pointer located in the SMM-accessible "communication buffer" or "swsmi" handler context, and (c) causing the SMM core to dereference the corrupted pointer when servicing the next SMI, executing the attacker's shellcode with SMM privileges.

Step 4 — Post-Exploitation Impact (SMM compromise)

• The attacker gains System Management Mode code execution. This enables:
  • Persistence: Writing to SPI flash (BIOS region) to re-flash a malicious firmware image that survives reinstalls and disk replacement.
  • Stealth: The attacker can hook SMI handlers to hide processes, files, and network activity from the OS and hypervisor, and can modify VMX root state to silently manipulate a running hypervisor.
  • Secure Boot bypass: Modifying Secure Boot keys (PK/KEK/db) in UEFI NVRAM to allow loading unsigned or malicious bootloaders.
  • Complete platform control: Direct access to all physical memory, MMIO, PCIe devices, and CPU MSRs, allowing the attacker to install a "ring -3" rootkit.

Impact Assessment

• CVSS 7.5 (High) — though High privileges are required, the confidentiality, integrity, and availability impact is HIGH across all three pillars (C:H/I:H/A:H), with a Scope Change (S:C) indicating that the compromise extends beyond the initial vulnerable component (the firmware driver) to the entire platform.

• Affected systems: Any desktop, laptop, server, or embedded device released with Insyde InsydeH2O firmware built from kernel 5.1 through 5.5. This spans a wide range of OEM vendors (from mainstream consumer laptops to enterprise servers). The affected module operates at the AHCI SATA controller level, so devices using NVMe-only storage or those without SATA ports may be less exposed, but the driver's presence is likely ubiquitous on platforms with SATA support.

• Business impact: While local High privilege is required, the consequence of a successful exploit is catastrophic — firmware-level persistence is considered one of the most severe threats to enterprise endpoint security. An SMM rootkit can survive OS reinstallation, disk replacement, and can subvert antivirus, EDR, and hypervisor- based defenses. For critical infrastructure and high-security environments, a compromised SMM means the platform must be considered untrusted at the hardware level; remediation requires flashing the SPI flash or hardware replacement.

• EPSS note: EPSS probability of exploitation in the wild is 0.00304 (22.8% percentile) — low current weaponization likelihood. This is a classic but complex UEFI vulnerability, and CISA has not added it to the Known Exploited Vulnerabilities catalog.

Detection Guidance

Given the local, low-level nature of this attack, network-based detection is impractical. Detection must focus on endpoint/EDR telemetry capturing SMI activity, firmware flash writes, unusual kernel/driver behavior, and memory-scanning tools capable of inspecting SMRAM.

Sigma Rule

title: Insyde AhciBusDxe SMM Memory Corruption Attempt (CVE-2022-24030)
status: experimental
description: Detects suspicious writes to SMBus or ACPI/MMIO regions that may indicate exploitation of Insyde InsydeH2O SMM memory corruption.
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2022-24030
author: Valtersit Threat Intel
logsource:
    category: driver_load
    product: windows
detection:
    selection_ioctl:
        Image|endswith:
            - '\System32\drivers\*'
        CommandLine|contains:
            - 'SMM'
            - 'Smram'
    selection_insyde:
        Description|contains:
            - 'Insyde'
            - 'InsydeH2O'
            - 'AhciBusDxe'
    condition: selection_ioctl and selection_insyde
level: high
falsepositives:
    - Known firmware update tools writing to BIOS/SMM regions during vendor patching
tags:
    - attack.execution
    - attack.persistence
    - cve.2022.24030

YARA Rule

rule CVE_2022_24030_Insyde_AhciBus
{
    meta:
        author = "Valtersit Threat Intel"
        description = "Detects SMRAM corruption indicators related to Insyde AhciBusDxe"
        cve_id = "CVE-2022-24030"
        date = "2025-01-01"

    strings:
        $s1 = "AhciBusDxe" ascii nocase fullword
        $s2 = "InsydeH2O" ascii nocase fullword
        $s3 = "SMram" ascii nocase
        $s4 = {56 4D 4F 53 51 20 45 72 72 6F 72} // "VMOSQ Error" common SMM driver string
        $s5 = {00 00 00 00 FF FF FF FF} // potential fixed-write signatures

    condition:
        (uint16(0) == 0x5A4D) and
        any of ($s1, $s2, $s3, $s4, $s5)
}

Suricata IDS Rule

Note: This is a local privilege escalation affecting firmware; no meaningful network-based detection is possible. The rule below is provided for completeness and will detect a rare attack vector where an attacker in an SMB/CIFS network environment attempts to deliver a malicious driver or a tool that triggers SMM communication via network share.

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"Possible CVE-2022-24030 Insyde AhciBusDxe exploitation tool download - SMM tool indicator"; content:"Insyde"; nocase; content:"SMM"; distance:100; within:200; classtype:attempted-admin; sid:3002411; rev:1; metadata:cve CVE-2022-24030;)

Elastic Detection

// Detect process loading drivers or calling device I/O with SMM-related strings
sequence by process.entity_id with maxspan=5m
  [process where event.type == "start" and
     process.command_line : ("*Insyde*", "*Smram*")]
  [file where event.type == "creation" and
     file.name : ("*.sys", "*.dll") and
     file.path : "*\\drivers\\*"]

Splunk SPL Query

index=windows sourcetype=WinEventLog:Microsoft-Windows-CodeIntegrity/Operational
| rename EventID as event_id
| where event_id=3033 OR event_id=3077
| search "Insyde" OR "SMram" OR "AhciBusDxe"
| table _time, Image, FilePath, ProcessName, EventID, Signature
| rex field=FilePath ".*(?<driver_used>\\\\(?:[^\\\\]+)\.sys)"

index=windows sourcetype=WinEventLog:System
| search "SMM" OR "SMRAM" OR "InsydeH2O"
| table _time, EventCode, Provider_Name, Message

Wazuh OSSEC Rule

<group name="insyde,smm,">
  <rule id="100231" level="12" frequency="8" timeframe="300">
    <if_matched_sid>502</if_matched_sid>
    <field name="win.system.eventID">10</field>
    <match>DeviceIoControl|Insyde|Smram|AhciBusDxe</match>
    <description>Potential exploitation of Insyde AhciBusDxe SMM memory corruption (CVE-2022-24030) - unusual device IOCTL activity targeting SMM.</description>
    <group>insyde,attack.execution,smm,</group>
    <mitre>
      <id>T1190</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 2/4 (CLAIMED — a single source (NVD) references a fix; not independently confirmed). Insyde has not publicly published a dedicated advisory for this CVE in a discoverable format as of this report.

1. Immediate Mitigations (if patch is unavailable)

• Restrict local access: Since the attack requires High privileges (local), ensure only trusted administrators have local interactive or kernel-level access to affected systems. Enforce least privilege for local users and service accounts.
• Enable SMM protection features in BIOS/firmware settings, if the platform exposes them:
  • Enable SMM_BWP (SMM BIOS Write Protection) to prevent SMM code from being modified.
  • Enable D_LCK for SMRAM locking after secure boot.
  • Enable UEFI Secure Boot to prevent the loading of unsigned drivers that could be used to trigger the flaw.
• Monitor for unauthorized BIOS/firmware updates and block tools that attempt to write to SPI flash (e.g., via EDR policies blocking wmic/Invoke-WebRequest scripts that invoke SPI flash writes).

2. Patch / Upgrade Steps

• Check with your OEM (original device manufacturer) for an updated InsydeH2O firmware that includes a fixed AhciBusDxe driver based on Insyde kernel 5.6 or later (the description states kernels 5.1 through 5.5 are affected, implying 5.6 contains the fix).
• Apply the vendor ODM/UEFI capsule update via the standard firmware update mechanism (Windows Update, Linux fwupd, or LVFS if the OEM provides it).
• Verify the update by checking the firmware version (e.g., fwupdmgr get-devices on Linux; GetBiosType in Windows PowerShell) and confirming the SMBIOS Firmware Version string indicates a kernel ≥ 5.6.

3. Long-Term Hardening

• Inventory and manage firmware versions across the fleet using a firmware assurance tool (e.g., eSP, NIST's Firmware Integrity Measurement) to flag any system running between kernel 5.1–5.5.
• Enable Intel Boot Guard or AMD Platform Secure Processor (PSP) verification of the firmware boot path, where supported, to ensure SMM image is authenticated.
• Implement runtime SMM monitoring (e.g., using Intel VT-d and posted interrupts) where feasible; this is a research-level control and mostly available in enterprise server platforms.
• Replace or decommission systems with end-of-life firmware support that will not receive an Insyde update.

References

1. NVD — CVE-2022-24030: https://nvd.nist.gov/vuln/detail/CVE-2022-24030
2. Insyde Software — InsydeH2O product page (vendor): https://www.insyde.com/products/insydeh2o
3. MITRE ATT&CK — T1190 Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
4. MITRE CWE — CWE-787 Out-of-bounds Write: https://cwe.mitre.org/data/definitions/787.html
5. CISA Known Exploited Vulnerabilities Catalog (CVE-2022-24030 not listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Threat actor activity: No known threat actor campaigns have been publicly attributed to this specific CVE at the time of writing. EPSS (0.003) suggests low weaponization; no exploit code has been released publicly.