How to get the AD object security ID (SID)
From Tech-Wiki
How to obtain the Active Directory Security ID (SID) for an object.
First obtain the distinguished name (DN) of the object. In this example the 'dsquery' utility has been used. From the Command Prompt.
dsquery user -name "Joe Bloggs"
Example Output:
"CN=Joe Blogs,OU=Users,DC=contoso,DC=com"
Next use the 'dsget' utility, along with the DN to obtain the SID:
dsget user "CN=Joe Blogs,OU=Users,DC=Contoso,DC=com" -sid
Example Output:
sid S-1-5-21-2560XXXX-XXXXX-XXXXX-19440 dsget succeeded