Detection server cannot pick up CCN in MS-Word doc with embedded XLS file

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Issue/Introduction

I have a Credit Card Number in a .xlsx file embedded in a Word document that is not being detected.  The Credit Card Number has no dashes or spaces, just a 16 digit number.

Resolution

 

MS Excel will, by default, only track 15 significant digits in a standard number cell, regardless of format and replace the rest with zeros!  Space delimited and dash delimited CCNs work fine.  With a straight 16 digit valid CCN number, Excel changed the last number to a 0. By changing the last digit to a 0, this is no longer a valid CCN and fails the Luhn check – Symantec DLP is working as designed and not picking it up to avoid a false positive. 

Also see: MS article 269370