Heisenberg Heisenberg - 24 days ago 7
Java Question

RegEx to account for null string

I wrote a regex for my SIEM to capture the Caller Computer Name for Windows Security Event 4740 - User Account Lockout.

The problem is that sometimes the "Caller Computer Name" field has a null or empty value and my regex does not account for it. The residual affect is that it is causing syntax problems in my custom email notification any time an event is captured with a blank value.

See link on Regex101:

Caller Computer Name:\s+([^ ]+)


The second occurrence of
Caller Computer Name:
is not found, but I want to find that substring. How do I write a Regex that accounts for either condition? Whether there is a value or not.

Ben Ben
Answer Source

The regex will match if there is an empty value since * matches for 0 or more oven if there is no character following the String.

/Caller Computer Name:\s*[^ ]*/