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Re: [Snort-users] help writing snort rule

To: <snort-users@lists.sourceforge.net>
Subject: Re: [Snort-users] help writing snort rule
From: "Bill Lopez" <Bill@oefi.org>
Date: Fri, 26 Jan 2007 10:58:41 -0800
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Thread-topic: Re: [Snort-users] help writing snort rule

Thank you for the quick response to my question. 

 

I don’t want to keep asking elementary questions in this forum if its not appropriate, please let me know if this isn’t the proper place and direct me to where I can ask basic questions.

 

I wasn’t able to get an alert on the bleeding rule

 

alert tcp any any -> any any (msg: "BLEEDING-EDGE SSN Detected in Clear Text"; flow: established; pcre:"/ ([0-6]\d\d|7[0-256]\d|73[0-3]|77[0-2])-\d{2}-\d{4} /"; classtype: policy-violation; sid: 2001328; rev:8; )

 

thus the reason for trying to write my own with a small variance in the character string –  

 

alert ip any any -> $EXTERNAL_NET any (pcre:"/\d{3}(\s|-)?\d{2}(\s|-)?\d{4}/"; msg:"SSN Detected in Clear Text"; sid: 1000004;)

 

which doesn’t produce an alert either – eventually I want to apply this filter to just traffic from/to mail , telnet, ftp (etc) servers – I can send any variance of xxx-xx-xxxx, xxxxxxxx  or xxx xx xxxx via an e-mail, text file attachment or file upload and still never see an alert to the console.  I have a simple rule to check for content using a keyword and get alerted when sending that keyword with e-mail, attachment and file upload (this was my test to see if snort was actually alerting correctly)  I am only running my test rules with an out of the box snort.conf file.

 

Why wouldn’t either of the above rules alert with (for example) an e-mail sent with 555-55-5555 in the body?

 

 

Bill Lopez

Operating Engineers Trust Funds

(626) 356-3524

(626) 255-1066

 

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