Identifiying windows users in Oracle

I am trying to identif开发者_JS百科y incoming user into Oracle in order to give them access right according to their identity (FGAC). Users are located in different domain's. which means that they might have identical system username (windows userename).

I have been trying to use the Environment context variable sys_context('userenv', 'var') where I get the Domain name (f.ex. SYS_CONTEXT('USERENV','HOST') and SYS_CONTEXT('USERENV','OS_USER')) but I seem to get different result's depending on the connection method.

Are there any other means of getting users true identity I can explore?

I'm not sure which variable you should use but you may want to look at select * from v$session to help you pick one.

If you're basing FGAC on OS_USER environment variable, you're truly not securing the data. OS_USER isn't a credential passed to Oracle, it's just a string that can be manipulated by an attacker.