topic Re: Would my search detect a malicious user, attempting to connect to multiple destinations, but only one failed login to each destination? in Splunk Search

Would my search detect a malicious user, attempting to connect to multiple destinations, but only one failed login to each destination?

jacqu3sy — Mon, 27 Feb 2017 10:44:43 GMT

Problem with this search?

Would the following search detect a malicious user, trying to connect to multiple destinations using a specific username, but only one failed login to each destination? My understanding is that the count against one specific destination would have to be greater than 5 for this to fire an alert.

| tstats `summariesonly` count from datamodel=Authentication where nodename=Authentication.Failed_Authentication by "Authentication.user","Authentication.dest"  
| rename "Authentication.user" as "user ","Authentication.dest" as "dest" 
| where 'count'>5

Would it however detect an attack against say, 100 destinations, where there was just 1 failed login against each host? Someone trying to brute force a username 'Administratror' for example and fly under the >5 trigger?

Thanks.

Re: Would my search detect a malicious user, attempting to connect to multiple destinations, but only one failed login to each destination?

DalJeanis — Mon, 27 Feb 2017 15:49:43 GMT

You are correct that it would not detect such an attack. You could set up an additional search (with perhaps a different threshold for triggering) by moving the "by destination" portion of the search, something like this.

 | tstats `summariesonly` count list ("Authentication.dest") as "dest" from datamodel=Authentication where nodename=Authentication.Failed_Authentication by "Authentication.user"
 | rename "Authentication.user" as "user "
 | where 'count'>10

Re: Would my search detect a malicious user, attempting to connect to multiple destinations, but only one failed login to each destination?

jacqu3sy — Mon, 27 Feb 2017 16:20:26 GMT

Thanks for confirming. Much appreciated.

I did try your alternative search but it returned;
Error in 'stats' command: The argument '(Authentication.dest)' is invalid.

I'll play around with it. Thanks again.

Re: Would my search detect a malicious user, attempting to connect to multiple destinations, but only one failed login to each destination?

DalJeanis — Wed, 01 Mar 2017 06:13:59 GMT

Sure. I wondered about that.

Look up the eventSearch value in the search.log for your original tstats search, and see what splunk substituted for "Authentication.dest" . Use that same underlying data model item in the "list() as dest" clause.