CVE-2025-58770

Executive Summary

CVE-2025-58770 is a vulnerability in AMI APTIOV BIOS firmware that allows a local attacker to exploit improper handling of insufficient permissions or privileges. This flaw can lead to escalation of authorization, potentially compromising system integrity and availability. The vulnerability is classified as local access, meaning an attacker must already have some level of system access to exploit it. No public proof-of-concept (PoC) or exploit code has been released, and the vendor (AMI) has not yet provided a patch. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild at this time.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in AMI APTIOV BIOS, which is a critical component in the hardware supply chain. Organizations should monitor AMI’s advisory channels for patch updates and consider hardware-level mitigations.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is unusual and likely indicates incomplete scoring data. Based on the description (local access, privilege escalation, impact on integrity and availability), a reasonable CVSS v3.1 vector would be:

• Attack Vector (AV): Local (L)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): Low (L)
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): None (N)
• Integrity (I): High (H)
• Availability (A): High (H)

Estimated CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Estimated Base Score: 7.1 (High)

Threat Level: High (due to potential for full system compromise via BIOS-level access).

Deep Dive & Mechanics

The vulnerability resides in the AMI APTIOV BIOS firmware, which is used in many motherboards and embedded systems. The core issue is Improper Handling of Insufficient Permissions or Privileges (CWE-274). This means the BIOS fails to properly enforce security checks when a local user attempts to perform privileged operations.

Mechanism:

1. A local attacker with low privileges (e.g., standard user account) can interact with the BIOS interface or UEFI runtime services.
2. Due to insufficient permission checks, the attacker can invoke functions that should require higher privileges (e.g., kernel or firmware-level access).
3. This allows the attacker to modify BIOS settings, disable security features (like Secure Boot), or execute arbitrary code in the firmware context.
4. Successful exploitation leads to escalation of authorization, potentially allowing the attacker to persist across reboots and compromise system integrity and availability.

Attack Vector: Local access (requires physical or remote desktop access to the system).

Vulnerable vs. Patched Code

No specific code snippets are available as this is a closed-source BIOS firmware. However, the vulnerability likely involves a missing or incorrect privilege check in the UEFI runtime driver or SMM (System Management Mode) handler.

Vulnerable Code (Hypothetical):

// Vulnerable: No privilege check before executing privileged operation
EFI_STATUS
VulnerableFunction(
    IN UINTN Parameter
)
{
    // Directly perform sensitive operation
    return SetNvVariable(L"SecureBoot", &NewValue);
}

Patched Code (Hypothetical):

// Patched: Added privilege check
EFI_STATUS
PatchedFunction(
    IN UINTN Parameter
)
{
    // Check if caller has sufficient privileges
    if (!IsCallerPrivileged()) {
        return EFI_ACCESS_DENIED;
    }
    return SetNvVariable(L"SecureBoot", &NewValue);
}

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Local access to a system with vulnerable AMI APTIOV BIOS.
• Low-privilege user account.
• Knowledge of the specific BIOS version and UEFI interface.

Exploitation Steps:

1. Reconnaissance: Identify the BIOS version using tools like dmidecode (Linux) or wmic bios get smbiosbiosversion (Windows).
2. Trigger Vulnerability: Use a custom UEFI application or script to call the vulnerable function. For example, using the UEFI Shell:

   # Hypothetical command to exploit the vulnerability
   VunerableApp.efi -set SecureBoot=Disabled
   

3. Escalate Privileges: Once Secure Boot is disabled, load an unsigned kernel driver or bootkit to gain kernel-level persistence.
4. Maintain Access: Install a firmware-level rootkit that survives OS reinstallation.

No public exploit code is available.

Blue Team (Defensive)

Detection:

• Monitor for unusual UEFI runtime calls or BIOS configuration changes.
• Use hardware security modules (TPM) to attest boot integrity.
• Enable Secure Boot and ensure it cannot be disabled without proper authorization.

Mitigation:

• Apply BIOS updates from the hardware vendor as soon as AMI releases a patch.
• Restrict physical access to systems.
• Use BIOS password protection and disable boot from external media.
• Implement UEFI Secure Boot with custom keys to prevent unauthorized firmware modifications.

Indicators of Compromise (IOCs)

• File Hashes: None available (no known malware associated).
• Registry Keys: N/A (BIOS-level).
• Network Signatures: N/A (local vulnerability).
• Process Names: Look for unusual UEFI applications or scripts running with high integrity.
• BIOS Logs: Unexpected changes to Secure Boot status or boot order.

Detection Engineering

YARA Rule

rule CVE_2025_58770_BIOS_Exploit {
    meta:
        description = "Detects potential exploitation of CVE-2025-58770 in AMI APTIOV BIOS"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58770"
    strings:
        $s1 = "SetNvVariable" ascii wide nocase
        $s2 = "SecureBoot" ascii wide nocase
        $s3 = "EFI_ACCESS_DENIED" ascii wide nocase
    condition:
        any of ($s1, $s2, $s3)
}

Sigma Rule

title: CVE-2025-58770 - AMI APTIOV BIOS Privilege Escalation
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to exploit improper permission handling in AMI APTIOV BIOS
author: Valters IT
logsource:
    product: windows
    service: system
detection:
    selection:
        EventID: 1
        Image|endswith: '\UEFI.exe'
        CommandLine|contains: 'SetNvVariable'
    condition: selection
falsepositives:
    - Legitimate BIOS updates
level: high

Suricata Rule

alert ip any any -> any any (msg:"CVE-2025-58770 - AMI APTIOV BIOS Exploit Attempt"; content:"|53 65 74 4E 76 56 61 72 69 61 62 6C 65|"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Vendor Patch: Await an official BIOS update from AMI or your hardware vendor. Check AMI’s security advisory page regularly.
2. Workaround: Enable BIOS password protection and disable boot from external media. Use TPM-based attestation to verify boot integrity.
3. Access Control: Restrict physical and remote desktop access to systems. Implement the principle of least privilege.
4. Monitoring: Deploy the provided YARA, Sigma, and Suricata rules to detect exploitation attempts.
5. Hardening: Enable Secure Boot with custom keys and ensure it cannot be disabled without physical presence.

Valters IT – Securing firmware, one patch at a time.