When configuring a Windows service to run under a specific user account, you'll notice the credentials aren't stored in plain text in the registry. The ObjectName value in HKLM\SYSTEM\CurrentControlSet\Services\YOUR-SERVICE only contains the username, leaving many developers wondering where and how the password is secured.

The Service Control Manager (SCM) handles credential storage using these mechanisms:

• The password is encrypted using the Local Security Authority (LSA) subsystem
• Encrypted credentials are stored in the HKLM\SECURITY\Policy\Secrets registry hive
• The LSA secret is protected by DPAPI (Data Protection API) at the system level

The Data Protection API plays a crucial role in securing service account credentials:

// Example of using DPAPI in C# to mimic similar protection
using System;
using System.Security.Cryptography;

public class ServiceCredentialProtection {
    public static byte[] Protect(byte[] data) {
        return ProtectedData.Protect(data, null, DataProtectionScope.LocalMachine);
    }
    
    public static byte[] Unprotect(byte[] data) {
        return ProtectedData.Unprotect(data, null, DataProtectionScope.LocalMachine);
    }
}

When working with service credentials:

• The password is set during service configuration via ChangeServiceConfig API
• Credentials are validated immediately and encrypted by the LSA
• Only SYSTEM-level processes can access the protected secrets

While not recommended for security reasons, here's how the system handles it internally:

// C++ example showing service credential query structure
#include <windows.h>
#include <winsvc.h>

void QueryServiceConfigExample(LPCTSTR serviceName) {
    SC_HANDLE hSCManager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
    SC_HANDLE hService = OpenService(hSCManager, serviceName, SERVICE_QUERY_CONFIG);
    
    if (hService) {
        DWORD bytesNeeded = 0;
        QueryServiceConfig(hService, NULL, 0, &bytesNeeded);
        
        LPQUERY_SERVICE_CONFIG config = (LPQUERY_SERVICE_CONFIG)LocalAlloc(LPTR, bytesNeeded);
        if (QueryServiceConfig(hService, config, bytesNeeded, &bytesNeeded)) {
            // config->lpServiceStartName contains the account name
            // Password is NOT accessible here
        }
        LocalFree(config);
        CloseServiceHandle(hService);
    }
    CloseServiceHandle(hSCManager);
}

When dealing with service accounts:

• Use managed service accounts (gMSA/sMSA) when possible
• Never attempt to extract or decrypt stored passwords
• Rotate service account passwords regularly
• Consider using Windows authentication tokens where appropriate

When configuring a Windows service to run under a specific user account, the password isn't stored in plaintext within the registry. The ObjectName value in HKLM\SYSTEM\CurrentControlSet\Services\SERVICE-NAME only contains the account name (either in DOMAIN\USER format or NT AUTHORITY\SYSTEM for local system).

Windows services store encrypted credentials using one of these mechanisms:

1. LSA Secrets (Local Security Authority)
   - Path: HKLM\SECURITY\Policy\Secrets
   - Only accessible by SYSTEM account
   
2. DPAPI (Data Protection API)
   - Uses machine-specific encryption keys
   - Protected Storage subsystem handles the encryption

The Data Protection API interacts with service management through these key components:

• Service Control Manager (SCM) calls LsaStorePrivateData when setting credentials
• Credentials are encrypted using machine-specific keys (derived from DPAPI)
• During service startup, SCM decrypts credentials using LsaRetrievePrivateData

While you can't directly access the encrypted password, here's how to query service configuration:

using System;
using System.ServiceProcess;

class Program {
    static void Main() {
        ServiceController sc = new ServiceController("MyServiceName");
        Console.WriteLine("Account: " + sc.ServiceName);
        Console.WriteLine("Type: " + sc.ServiceType);
        Console.WriteLine("Status: " + sc.Status);
    }
}

Microsoft's security model prevents direct password retrieval because:

• DPAPI encryption is tied to the machine or domain
• Access requires SYSTEM privileges even for read operations
• Credential Guard protects against memory scraping attacks

For applications requiring service account credentials:

// Using managed service accounts (recommended)
sc.exe config MyService obj= "NT AUTHORITY\NETWORK SERVICE"

// Using group managed service accounts
sc.exe config MyService obj= "DOMAIN\gmsa_account$"

Managed service accounts automatically handle password rotation without exposing credentials.