CVE-2025-27813

Executive Summary

CVE-2025-27813 is a high-severity vulnerability in MSI Center, a system management and monitoring utility for MSI hardware. The flaw is a Missing PE Signature Validation (CWE-347), meaning the application fails to properly verify the digital signature of Portable Executable (PE) files before loading or executing them. This allows a local attacker with standard user privileges to load an unsigned or maliciously signed binary, leading to arbitrary code execution in the context of the MSI Center process, which often runs with elevated privileges.

The vulnerability affects MSI Center versions prior to 2.0.52.0. The CVSS v3.1 score is 8.1 (High), with a vector emphasizing local access, low complexity, and high impact on confidentiality, integrity, and availability. The EPSS score is 0.0%, indicating no active exploitation in the wild at the time of analysis, but the risk remains significant for targeted attacks.

No public proof-of-concept (PoC) code or exploit is available. The vendor has not released a patch, and the status remains UNKNOWN / UNPATCHED. This report provides detection rules, exploitation analysis, and mitigation strategies.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Local (L) – The attacker must have local access to the system.
• Attack Complexity (AC): Low (L) – No special conditions or race conditions required.
• Privileges Required (PR): Low (L) – The attacker needs standard user privileges.
• User Interaction (UI): None (N) – No user action required beyond the attacker's own.
• Scope (S): Changed (C) – The vulnerable component (MSI Center) can impact resources beyond its security scope.
• Confidentiality (C): High (H) – Full disclosure of sensitive data is possible.
• Integrity (I): High (H) – Complete compromise of system integrity.
• Availability (A): High (H) – Full denial of service or system crash.

Threat Level: High. The vulnerability allows privilege escalation from a standard user to SYSTEM-level code execution, bypassing signature enforcement.

Deep Dive & Mechanics

MSI Center is a Windows application that provides hardware monitoring, overclocking, and system tuning. It loads various PE files (DLLs, drivers, executables) to perform its functions. The vulnerability lies in the PE signature validation routine. When MSI Center loads a binary, it should check the digital signature to ensure the file is from a trusted publisher (MSI or Microsoft). However, due to a missing or incomplete validation check, the application will load any PE file, including those with invalid or missing signatures.

Attack Scenario:

1. An attacker gains local access to a system (e.g., via phishing, malware, or physical access).
2. The attacker places a malicious DLL or executable in a location that MSI Center will load (e.g., a plugin directory, a temp folder, or via a path traversal).
3. MSI Center loads the malicious binary without verifying its signature.
4. The malicious code executes with the privileges of MSI Center, which often runs as SYSTEM or with high integrity.
5. The attacker can then install backdoors, exfiltrate data, or pivot to other systems.

Root Cause: The WinVerifyTrust API or equivalent signature verification function is either not called, called incorrectly, or its return value is ignored. This is a classic case of CWE-347: Improper Verification of Cryptographic Signature.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable: No signature check
HMODULE hModule = LoadLibrary(L"malicious.dll");
if (hModule) {
    // Execute code from the DLL
}

Patched Code (Conceptual):

// Patched: Signature verification before loading
WINTRUST_DATA wtd = {0};
// ... initialize WINTRUST_DATA ...
LONG status = WinVerifyTrust(NULL, &guidActionID, &wtd);
if (status == ERROR_SUCCESS) {
    HMODULE hModule = LoadLibrary(L"trusted.dll");
    if (hModule) {
        // Execute code from the DLL
    }
} else {
    // Log error and reject the file
}

The patched version uses WinVerifyTrust to check the digital signature of the PE file before loading it. If the signature is invalid or from an untrusted publisher, the file is rejected.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a Windows system with MSI Center < 2.0.52.0 installed.
• Ability to write files to a directory that MSI Center loads (e.g., C:\Program Files\MSI Center\Plugins\ or %TEMP%).

Exploitation Steps:

1. Identify Load Paths: Use Process Monitor (Procmon) to monitor MSI Center's file operations and identify directories where it loads PE files without signature checks.
2. Craft Malicious DLL: Create a DLL that executes a reverse shell or adds a local admin user.

   // malicious.cpp
   #include <windows.h>
   BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
       if (ul_reason_for_call == DLL_PROCESS_ATTACH) {
           // Execute command: add user to Administrators group
           system("net user attacker P@ssw0rd! /add");
           system("net localgroup Administrators attacker /add");
       }
       return TRUE;
   }
   

3. Compile and Sign (Optional): Compile the DLL and optionally sign it with a self-signed certificate (though the vulnerability bypasses signature checks).
4. Deploy: Copy the DLL to the identified load path.
5. Trigger Load: Restart MSI Center or trigger a function that loads the DLL (e.g., opening a specific tab).
6. Escalate: The DLL executes with SYSTEM privileges, granting full control.

Note: No public exploit code is available. The above is a conceptual demonstration.

Blue Team (Detection & Response)

Detection Steps:

1. Monitor File Writes: Alert on new DLL or EXE files written to MSI Center directories (e.g., C:\Program Files\MSI Center\*).
2. Process Anomaly Detection: Detect MSI Center loading unsigned binaries using Sysmon Event ID 7 (Image loaded) with signature validation.
3. Behavioral Analysis: Look for MSI Center spawning child processes like cmd.exe or powershell.exe.
4. Hunt for Known Bad: Search for DLLs with unusual names or from non-MSI publishers in MSI Center's process memory.

Response:

• Isolate the affected system.
• Terminate the MSI Center process.
• Remove the malicious binary.
• Review system logs for lateral movement.
• Apply the patch when available.

Indicators of Compromise (IOCs)

Detection Engineering

YARA Rule

rule CVE_2025_27813_MSI_Center_Signature_Bypass {
    meta:
        description = "Detects MSI Center loading unsigned PE files"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-27813"
    strings:
        $s1 = "MSI Center" wide ascii nocase
        $s2 = "LoadLibrary" wide ascii nocase
        $s3 = "WinVerifyTrust" wide ascii nocase
    condition:
        $s1 and not $s3 and $s2
}

Sigma Rule

title: MSI Center Unsigned Binary Load
id: 7b8c9d0e-1f2a-3b4c-5d6e-7f8a9b0c1d2e
status: experimental
description: Detects MSI Center loading a PE file without signature validation
author: Valters IT
date: 2025-04-10
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 7
        Image|endswith: '\MSICenter.exe'
        Signed: false
    condition: selection
falsepositives:
    - Legitimate unsigned MSI plugins (rare)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (
    msg:"CVE-2025-27813 - MSI Center Potential C2 Beacon";
    flow:to_server,established;
    content:"MSI Center"; http_user_agent;
    pcre:"/MSI Center/i";
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Update MSI Center: Upgrade to version 2.0.52.0 or later when available.
2. Restrict Local Access: Limit user privileges on systems running MSI Center.
3. Application Control: Use AppLocker or Windows Defender Application Control (WDAC) to block unsigned binaries.
4. Monitor: Deploy the YARA, Sigma, and Suricata rules above.

Long-Term Fix:

• The vendor must implement proper PE signature validation using WinVerifyTrust or equivalent.
• Enforce code signing for all plugins and modules.
• Run MSI Center with least privilege (e.g., as a standard user) where possible.

Workaround:

• Disable MSI Center if not required.
• Use Process Monitor to identify and block unauthorized DLL loads.

Valters IT