What does the Google dork "allintext:user filetype:log" search for?

[Caserco]

I've seen the query allintext:user filetype:log mentioned in security and OSINT contexts. What exactly does this search return? Is it used for ethical security research, and what should site owners do to prevent sensitive log files from being indexed?

 

[Avika]

This Google dork finds publicly accessible log files with the word "user" in them. Security researchers use it to discover sensitive information such as user data, IP addresses or trails. Webmasters can use a robots.txt file or limit server access to keep these files out of the index.