A 17-year-old boy who hacked TalkTalk will be sentenced on Tuesday for his role in the multi-million pound data breach.
The teenager, who cannot be named for legal reasons, found a vulnerability in the website using "legitimate software" and shared details of it online, an earlier hearing at Norwich Youth Court was told.
While he did not exploit the information for monetary gain, the TalkTalk website was targeted more than 14,000 times after the boy exposed the vulnerability.
He told magistrates "I was just showing off to my mates" as he admitted seven hacking offences.
Telecoms giant TalkTalk fell victim to what it described as a "significant and sustained" attack on its website in October 2015 and the firm said the fallout from the cyber attack cost it £42 million.