Splunk Search

Using Machine Learning Toolkit to detect auth abuse

patpro
Path Finder

Hello,

I’m trying to tune Machine Learning Toolkit in order to detect authentication abuse on a web portal (based upon Lemon LDAP-NG).

My logs look like this:

(time/host/... header) client=(IP address) user=(login) sessionID=(session-id) mail=(user email address) action=(various statuses: connected / non-existent user / wrong pwd…)
 
I would like to train the Machine Learning Toolkit so that I can detect anomalies. Those anomalies can be:
- that client has made auth attempts for an unusual number of logins
- that client has made auth attempts for both non-existing and existing users
- …
 
So far it fails hard.
 
I’ve trained a model like this on approx. a month of data:

 

index="webauth" ( TERM(was) TERM(not) TERM(found) TERM(in) TERM(LDAP) ) OR TERM(connected) OR TERM(credentials) linecount=1 | rex "action=(?<act>.*)" | eval action=case(match(act,".* connected"), "connected", match(act,".* was not found in LDAP directory.*"), "unknown", match(act, ".* credentials"),"wrongpassword") | bin span=1h _time | eventstats dc(user) AS dcUsers, count(user) AS countUsers BY client,_time,action|search dcUsers>1|stats values(dcUsers) AS DCU,values(countUsers) AS CU BY client,_time,action| eval HourOfDay=strftime(_time,"%H") 
| fit DensityFunction CU by "client,DCU" as outlier into app:TEST

 

 
Then I’ve tested the model on another time interval where I know there is a big anomaly, by replacing the fit directive by "apply (model-name) threshold=(various values)".
No result.
 
So I guess I’m not on the right track to achieve this. Any help appreciated!
 
Tags (1)
0 Karma
Get Updates on the Splunk Community!

Splunk Search APIを使えば調査過程が残せます

   このゲストブログは、JCOM株式会社の情報セキュリティ本部・専任部長である渡辺慎太郎氏によって執筆されました。 Note: This article is published in both Japanese ...

Integrating Splunk Search API and Quarto to Create Reproducible Investigation ...

 Splunk is More Than Just the Web Console For Digital Forensics and Incident Response (DFIR) practitioners, ...

Congratulations to the 2025-2026 SplunkTrust!

Hello, Splunk Community! We are beyond thrilled to announce our newest group of SplunkTrust members!  The ...