Here is a good strat to validating the SSN

var text RemoveDashes = SearchAndReplace([SSN],"-","");

var text DigitOne = Mid($RemoveDashes,1,1);

var text DigitTwo = Mid($RemoveDashes,2,1);

var text DigitThree = Mid($RemoveDashes,3,1);

var text DigitFour = Mid($RemoveDashes,4,1);

var text DigitFive = Mid($RemoveDashes,5,1);

var text DigitSix = Mid($RemoveDashes,6,1);

var text DigitSeven = Mid($RemoveDashes,7,1);

var text DigitEight = Mid($RemoveDashes,8,1);

var text DigitNine = Mid($RemoveDashes,9,1);

(Contains("0123456789", $DigitOne) or $DigitOne = "")

and

(Contains("0123456789", $DigitTwo) or $DigitTwo = "")

and

(Contains("0123456789", $DigitThree) or $DigitThree = "")

and

(Contains("0123456789", $DigitFour) or $DigitFour = "")

and

(Contains("0123456789", $DigitFive) or $DigitFive = "")

and

(Contains("0123456789", $DigitSix) or $DigitSix = "")

and

(Contains("0123456789", $DigitSeven) or $DigitSeven = "")

and

(Contains("0123456789", $DigitEight) or $DigitEight = "")

and

(Contains("0123456789", $DigitNine) or $DigitNine = "")

and

(Length($RemoveDashes)=0 or Length($RemoveDashes)=4 or Length($RemoveDashes)=9)