[Zeek] sethhall/credit-card-exposure

[Nick Turley]

We’ve been meaning to share some of our work with the community so this has prompted a call to action :)

Nick Turley
Security Architect
CES Security Operations Center
Office: (801) 422-4994 | Cell: (801) 310-3816 | nick_turley at byu.edu
________________________________
From: Michael Shirk <shirkdog.bsd at gmail.com>
Sent: Thursday, December 12, 2019 7:19:53 AM
To: Nick Turley <nick_turley at byu.edu>
Cc: Scot Harris <SHARRIS at hollywoodfl.org>; zeek at zeek.org <zeek at zeek.org>
Subject: Re: [Zeek] sethhall/credit-card-exposure

You can submit a pull request to Seth's GitHub repo if you can share the modifications with the community.

--
Michael Shirk
Daemon Security, Inc.
https://www.daemon-security.com

On Thu, Dec 12, 2019, 09:18 Nick Turley <nick_turley at byu.edu<mailto:nick_turley at byu.edu>> wrote:
We’ve had pretty good luck with the package but we had to make modifications to get it working the way we wanted. We also modified it so it would work on Corelight. We’ve been running it on our Bro 2.6 cluster for some time. SSN detection is a high false positive game in a large environment like ours, so our analysts are still required to review the extracted payload and make a determination.

Some of the modifications include extracting a chunk of the payload where the SSN was detected and including that in the notice log. We also added the protocol that was detected and associated info. For example, if SMB, we include the file name and location identified. As I recall, there was also a bug we fixed that wasn’t masking the SSNs correctly.

We also feed in all 50 state historical SSN prefixes and include the state data in the notice log. However, SSNs after 2011 I believe are now randomized so this will be less effective over time.

While we get a number of false positives, the module has also helped us discover some fairly serious security issues.

When I get to the office, I would be happy to share our code.

Nick Turley
Security Architect
CES Security Operations Center
Office: (801) 422-4994 | Cell: (801) 310-3816 | nick_turley at byu.edu<mailto:nick_turley at byu.edu>
________________________________
From: zeek-bounces at zeek.org<mailto:zeek-bounces at zeek.org> <zeek-bounces at zeek.org<mailto:zeek-bounces at zeek.org>> on behalf of Scot Harris <SHARRIS at hollywoodfl.org<mailto:SHARRIS at hollywoodfl.org>>
Sent: Thursday, December 12, 2019 6:26:27 AM
To: zeek at zeek.org<mailto:zeek at zeek.org> <zeek at zeek.org<mailto:zeek at zeek.org>>
Subject: [Zeek] sethhall/credit-card-exposure


Does anyone have experience with the sethhall/credit-card-exposure package?



I installed it and it is generating some results that does not seem valid.



Running zeek 3.0 with this package installed using zkg.



The odd data includes packets that go from my workstation to the zeek main server on port 80 that is flagged as having credit card numbers in it.



I don’t think that actually occurred.



So was wondering if someone else had that package and what kind of results they are getting.



Thank you.







__________________________________________
Scot Harris
Network Engineer
City of Hollywood
Information Technology

P.O. Box 229045
Hollywood, FL 33022-9045
Office: 954-921-3304
E-mail: SHARRIS at hollywoodfl.org<mailto:SHARRIS at hollywoodfl.org>
[www.hollywoodfl.org]
Notice: Florida has a broad public records law. All correspondence sent to the City of Hollywood via e-mail may be subject to disclosure as a matter of public record.
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