RE: Using Snort to find creditcard data?

["Srinivasa Addepalli" <srao () intoto com>]

Hi,

Credit card numbers are typically 13 to 16 digits long. You can write a
signature to look for 13 to 16 continuous digits. There could be some cases
where it can generate false positives. You may have to live with false
positives in snort. I don't think snort has any keyword to check sequence of
digits represent a credit card number. Note that Luhn formula is one method
to check whether digits represent a credit card number. 

In addition to this administrator can create rules himself to filter out
clear connections that are expected to be secured by SSL. He/She can make
list of URLs that must be under SSL protection and ensure that these URLs
are not seen in HTTP requests in clear.

Srini



-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com] On
Behalf Of jerikl75 () gmail com
Sent: Wednesday, September 26, 2007 12:36 PM
To: focus-ids () securityfocus com
Subject: Using Snort to find creditcard data?

Would it be possible to write a Snort rule that triggers on possible
creditcard numbers and how would it look like?
PCI standars says that all creditcard data should be encrypted, It woild be
nice to verify that no card data shows up where it shouldn't...

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