Search using regex

[v_2nas (Nav)]

Hi Folks,

I am searching for specific event (4624) and where targetusername doesn’t match computername.
The computer accounts in Windows is denoted by a $ at the end of the name.

Regex in search assistance

I am trying to build a regex to match strings as follows: PDCS-MBX01$ pluto$ 12-2423$ I tried using the following: winlogbeat_event_data_SubjectUserName:(\w\W)+$ I thought the search should have been: [\w\W]+$, but Graylog does not like the [ or ] characters. Can anyone assist with a regex that will be accepted by Graylog and match all three of the above string types?

So i used the regex provide in above thread. The regex ([\w-]+$) works when i test in online regexr.com
However, when i used in graylog search it failed.

My idea is to exclude all 4624 events where TargetUserName is a computer account.

[jan (Jan Doberstein)]

your query did not look like the one that is provided by jochen:

Regex in search assistance

$ is a special character in regular expressions meaning “end of input”. The following regular expression will match these strings: ([\w-]+\$) You can play around with your regular expressions on pages like http://www.freeformatter.com/java-regex-tester.html.

[v_2nas (Nav)]

This regular expression
([\w-]+$)
works with java regex tester

but the same regular expression gives error in graylog search EventID:4624 AND TargetUserName:([\w-]+$)
Failed to parse query [EventID:4624 AND TargetUserName:([\w-]+$)]
Failed to parse query [EventID:4624 AND TargetUserName:([\w-]+$)]
Failed to parse query [EventID:4624 AND TargetUserName:([\w-]+$)]

[v_2nas (Nav)]

[jochen]

@v_2nas

but the same regular expression gives error in graylog search EventID:4624 AND TargetUserName:([\w-]+$)

Yes, because that’s the wrong query syntax.

Try the following query:

EventID:4624 AND TargetUserName:/.+/

Also be reminded that the regular expression has to match the complete field content if the field hasn’t been tokenized/analyzed.

See Regexp Query | Elasticsearch Reference [5.6] | Elastic for details about the Lucene regular expression syntax.

[v_2nas (Nav)]

i was basing it on the regex i found on the community.
I don’t have much understanding of the regex, so i do some trial and error using what is available.

([\w-]+) matches the the condition in java regex tester, but as you mentioned, it's incorrect for graylog. i have tried to use \ char for but that didn’t work.

I need to exclude all those events where name contains a computer name preceded by , something like abcd, abcdefg$, etc.

[jochen]

@v_2nas

I don’t have much understanding of the regex, so i do some trial and error using what is available.

That’s why I’ve pointed you to the documentation.

[v_2nas (Nav)]

I manage to get assistance from another graylog ninja, so thought i will share the solution to help anyone who is in the same situation.
So, we enabled allow_leading_wildcard_searches=true in the server.conf file
Then i could use this search query to get all user minus computer accounts.

EventID:4624 AND NOT TargetUserName:*$