gray hat

[ grey hat ]
/ ˈgreɪ ˈhæt /

noun Digital Technology, Informal.

a hacker who violates the security of a system without true malicious intent but often without the prior knowledge or consent of the owner or developer, and who later reports system vulnerabilities to the authorities, sometimes for personal profit.
See also black hat, white hat.

Origin of gray hat

First recorded in 1995–2000