Throughout the series, we find that Sarah doesn't like discussing her past. This arc really comes into play during the episode where she meets up with an old college friend in the Orange Orange and her name during college is revealed to have been Jennifer Burton.
Sometime later, Daniel Shaw starts calling Sarah by the name "Sam", stating this to be her real name, and judging by the reaction he consistently gets from Sarah when he calls her this, this is probably her actual real name. However, her surname doesn't ever seem to get mentioned.
Did we ever actually find out Sarah's full real name?