Hacker Croll, the hacker who embarrassed Twitter a year ago by making hundreds of its confidential corporate documents public, received a five-month suspended prison sentence last week. The Frenchman was also responsible for accessing without authorization the Twitter profiles of several celebrities including US President Barack Obama.

By his true name Francois Cousteix, the infamous Hacker Croll is a 24-year-old still living with his mother in the city of Beaumont, central France. Back in March, the French police caught up with him after an investigation that lasted several months and involved cooperation from the FBI.

After questioning, the self-confessed computer security enthusiast admitted his involvement in two separate security breaches which involved Twitter and its employees. However, he claimed his motive was to raise awareness about the risks of social engineering, a technique he used in both attacks.

The first incident occurred in Aprial 2009 and involved Twitter’s Director of Product Management, Jason Goldman, whose administrative password Croll obtained after hacking into his Yahoo! email account. Using Goldman’s credentials, Cousteix was able to view private information like e-mail address, mobile phone number or blocked users list from the accounts of Barack Obama, Britney Spears, Ashton Kutcher, Lily Rose Allen and others.

A few months later, with information obtained after compromising the personal Gmail account of another Twitter employee, the hacker was able to access Twitter’s corporate document sharing system. Cousteix downloaded hundreds of internal memos, executive meeting notes, financial projections, partner agreements, as well as other confidential documents and leaked them to TechCrunch. “It’s a message I wanted to get out to Internet users, to show them that no system is invulnerable,” the French hacker told France 3 television after his arrest in March. “The verdict is satisfying, given all the media pressure that built up,” commented Jean-Francois Canis, Cousteix’s attorney for The Huffington Post.