Splunk Enterprise Security
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Find anomalous network traffic of a user

New Member

Hi team,

I m trying to find network traffic of a user and classify it as high or normal based on avg and stdev calculations

QUERY :
index="panlogs" sourcetype="pan:traffic" user!=unknown | stats sum(bytes) as bytes by _time,user |eval MB = round(bytes/1024/1024,4)|bin span=1d _time | stats avg(MB) as avg stdev(MB) as stdv by user,time|eval avg = round(avg,4) , stdv = round(stdv,4) | eval Volume_Type= if((avg+2*stdv)> MB , "HIGH" , "NORMAL

However the avg and stdev calculation is wrong here as it collects per day basis and not when i keep it for last 7 days.

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Re: Find anomalous network traffic of a user

Motivator

Splunk has built in functionality to make this much easier. Try using "anomalies" and/or "anomalousvalue"

https://docs.splunk.com/Documentation/Splunk/8.0.1/SearchReference/Anomalies

https://docs.splunk.com/Documentation/Splunk/8.0.1/SearchReference/Anomalousvalue

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Re: Find anomalous network traffic of a user

New Member

Thanks for the response.However i am not sure of the threshold value to be set as it can change user to user hence i calculated it based on avg and stdev .i understand we can use streamstats command but i am unable to calculate avg for last 7 days as i had already bin for 1 day at start.

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