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

book

Article ID: 159729

calendar_today

Updated On:

Products

Data Loss Prevention Endpoint Prevent Data Loss Prevention Network Monitor Data Loss Prevention Network Prevent for Email Data Loss Prevention Network Prevent for Web Data Loss Prevention Network Protect Data Loss Prevention Endpoint Discover

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