Programmatically find the computer SID with C# and CPP

Posted on 2009-04-01
Last Modified: 2012-05-06
In need 2 routines, one in cpp and the other in C#. The code shows the cpp code to get the SID for the computer. I think this is correct, I have been using it for awhile. Then I need to be able to do the same thing in C#. Neither program will have administrative rights.

When I run these 2 code snipits on a computer on a domain I get the domain SID for the computer. I can verify this with ADSIViewer. Same results for both! Good, half way there.

If I then move the code to a machine that is not on a domain the CPP code will return a SID. But the .net C# code always throws no matter what computer name I give it.

This can't be that hard. So if someone has some ideas....


//	Get the size of the buffers


  cbSid        = 0;

  cbDomainName = 0;

  Sid          = NULL;

  LookupAccountName( NULL, szAccount, Sid, &cbSid, pszDomainName, &cbDomainName,  &eUse );


//	Now get the actual SID


  Sid           = (PSID)  malloc(cbSid);

   pszDomainName = (LPSTR) malloc(cbDomainName);

   bRC = LookupAccountName( NULL, szAccount, Sid, &cbSid, pszDomainName   , &cbDomainName, &eUse ); 

  if( bRC )


    strcpy_s( m_szDomainName, sizeof(m_szDomainName), pszDomainName );   	

    bRC = ConvertSidToStringSid( Sid, &pszSid ); 

    if( bRC )


     sprintf_s( szWork, sizeof(szWork), "       FQDN : %s\\%s   - SID_NAME_USE: %li",     m_szDomainName,  m_szComputerName, eUse);

  printf( "%s\r\n", szWork ); 			

  strcpy_s( m_szMachineSID, sizeof(m_szMachineSID), pszSid );

  printf( "  MachineSID: %s\r\n", m_szMachineSID );    			

  if (pszSid)	LocalFree( pszSid );



==================================  C#  ===============================

	String sSid;

	SecurityIdentifier sid, sid2;

	NTAccount nta, acct;



		nta = new NTAccount( "SNORBERG-T5400$" );	


		sid = (SecurityIdentifier) nta.Translate( typeof(SecurityIdentifier));

		sSid = m_Config.MachineSID;

		sid2 = new SecurityIdentifier( sSid + "-513");


		acct = (NTAccount)sid.Translate(typeof(NTAccount));	

		acct = (NTAccount)sid2.Translate(typeof(NTAccount));


	catch( Exception ex )


		MessageBox.Show( ex.Message );


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Question by:snorberg
LVL 21

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Accepted Solution

snorberg earned 0 total points
Comment Utility
It seems that the only way this can be done from .net code is by using the win32 api commands through the runtime.interopServices.
The pinvoke site has a reasonable example.

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