Splunk Search

Regular Expression to match credit cards

oscargarcia
Path Finder

Hi,

I am trying to write a search to look for credit card numbers in logs (for the PCI requirement 3.1, of course 🙂

I came across this:

^((67\d{2})|(4\d{3})|(5[1-5]\d{2})|(6011))(-\s\d{4}){3}|(3[4,7])\d{2}-\s\d{6}-\s\d{5}$

Which is said to match most credit card data, but I am struggling to find a way to translate this into an splunk search.

Can anybody help?

Many thanks

Tags (2)
0 Karma
1 Solution

dwaddle
SplunkTrust
SplunkTrust

You can define this as a search-time extracted field and do searches for events where that field has a value.

http://www.splunk.com/base/Documentation/latest/Knowledge/Addfieldsatsearchtime

Taking your regex above, and plugging it into transforms.conf like so:

[possible_credit_card_no]
REGEX=^((67\d{2})|(4\d{3})|(5[1-5]\d{2})|(6011))(-\s\d{4}){3}|(3[4,7])\d{2}-\s\d{6}-\s\d{5}$
FORMAT=possible_cardno::$1

Then referencing it in props.conf:

[mysourcetype]
REPORT-cardno=possible_credit_card_no

View solution in original post

dwaddle
SplunkTrust
SplunkTrust

You can define this as a search-time extracted field and do searches for events where that field has a value.

http://www.splunk.com/base/Documentation/latest/Knowledge/Addfieldsatsearchtime

Taking your regex above, and plugging it into transforms.conf like so:

[possible_credit_card_no]
REGEX=^((67\d{2})|(4\d{3})|(5[1-5]\d{2})|(6011))(-\s\d{4}){3}|(3[4,7])\d{2}-\s\d{6}-\s\d{5}$
FORMAT=possible_cardno::$1

Then referencing it in props.conf:

[mysourcetype]
REPORT-cardno=possible_credit_card_no
Get Updates on the Splunk Community!

Why You Can't Miss .conf25: Unleashing the Power of Agentic AI with Splunk & Cisco

The Defining Technology Movement of Our Lifetime The advent of agentic AI is arguably the defining technology ...

Deep Dive into Federated Analytics: Unlocking the Full Power of Your Security Data

In today’s complex digital landscape, security teams face increasing pressure to protect sprawling data across ...

Your summer travels continue with new course releases

Summer in the Northern hemisphere is in full swing, and is often a time to travel and explore. If your summer ...