Starting service as a user with no password

Question

I'm trying to start a service as a user and things work fine, until I try a user that doesn't have a password. Then, it fails to start (due to log-on error).

Am I doing something wrong or is this "by design"?

The code to register this service:

    SC_HANDLE schService = CreateService( 
        schSCManager,           
        strNameNoSpaces,      
        strServiceName,           
        SERVICE_ALL_ACCESS,       
        SERVICE_WIN32_OWN_PROCESS, 
        SERVICE_AUTO_START,    
        SERVICE_ERROR_NORMAL,      
        szPath,                  
        NULL,                     
        NULL,                  
        NULL,                    
        strUser,
        (strPassword.IsEmpty())?NULL:strPassword);

Answer 1

It may be due to an OS security requirement or security policy. Check the security policies to see if anything is relevant there.

Answer 2

Yes, it was indeed related to the security policy. To elaborate:

http://technet.microsoft.com/en-us/library/bb457114.aspx

"If you want to disable the restriction against logging on to the network without a password, you can do so through Local Security Policy. The policy setting that controls blank password restriction can be modified using the Local Security Policy or Group Policy MMC snap-ins. You can use either tool to find this policy option at Security Settings\Local Policies\Security Options. The name of the policy is Accounts: Limit local account use of blank passwords to console logon only. It is enabled by default."

After disabling that, it all works fine.

Answer 3

You need to specify an empty string, not NULL if there is no password. NULL is not a valid empty string, "" is. Probably you should just pass strPassword for the last parameter.

SC_HANDLE schService = CreateService( 
            schSCManager,           
            strNameNoSpaces,      
            strServiceName,           
            SERVICE_ALL_ACCESS,       
            SERVICE_WIN32_OWN_PROCESS, 
            SERVICE_AUTO_START,    
            SERVICE_ERROR_NORMAL,      
            szPath,                  
            NULL,                     
            NULL,                  
            NULL,                    
            strUser,

// change this line to:
            strPassword.IsEmpty() ? L"" : strPassword);
// or maybe
            strPassword);

Answer 4

Thank you - I've tried that first actually, but to no avail.

If I start services.msc, manually go into service properties and clear the 2 password fields, then press "Apply" and try to start it, it also fails.