As per the reports, thousands of people using the websites Facebook and Twitter informed that there had been tampering of web-pages and videos of Justin Bieber on YouTube.

The hackers targeted Justin Bieber the sensational singer, injecting software into his YouTube pages leading to poor messages for visitors about the teen celebrity. It has been speculated that the harm caused to YouTube users may range from having their computers contaminated with malicious programs to being diverted to other websites projecting adult content.

The security researchers described the attack as involving a malformed HTML that hackers intentionally employed to bypass HTML sanitization checks on YouTube's comments sections.

A Google spokesman said that within 60-mins of the problem discovery, a default system for briefly hiding comments was implemented. The company issued a complete solution towards rectifying the problem within 2-hrs. A study was going on of the flaw for the prevention of similar problems henceforth, the spokesman continued, as reported by NetworkWorld on July 2, 2010.

The spokesman also stated that the attackers could not use their assault for accessing Google accounts. To stay safe, it is recommended that YouTube users first log out and then log-in into their accounts.

The attacks were thought to be because of the Internet forum 4Chan; however, it is believed that no sooner was the hack found, others started playing a role too.

YouTube stated that it was doing everything necessary to restore order via blocking or erasing comments from several of the site's pages.

Meanwhile, the attack seemed to coincide with the day when iTunes App Store was apparently found hacked. As per a warning, fake software compromised iTunes App Store of Apple and fraudsters bought things from victims' credit cards illegally.

Overall people using YouTube are advised to be very careful, particularly when browsing content associated with Bieber. Besides, accountholders of App Store should remain vigilant of any abnormal operation.