Hackers allegedly linked to the Anonymous group have gained access to Twitter user names, passwords, email addresses and other information belonging to as many as 250,000 user accounts. Earlier, a similar spate of cyber attacks had threatened leading media conglomerates New York Times and the Wall Street Journal, which attributed the attacks to hackers originating in China.

Twitter has not linked any of the attacks to China and attributed the attack to an extremely sophisticated group of hackers saying: "This attack was not the work of amateurs, and we do not believe it was an isolated incident. The attackers were extremely sophisticated, and we believe other companies and organisations have also been recently similarly attacked."

Describing the steps taken to prevent further security compromises with the affected user accounts, Twitter had this to say:

"As a precautionary security measure, we have reset passwords and revoked session tokens for these accounts. If your account was one of them, you will have recently received (or will shortly) an email from us at the address associated with your Twitter account notifying you that you will need to create a new password. Your old password will not work when you try to log in to Twitter."

Addressing its 200 million-strong active monthly user base, Twitter stated that it was working with government and federal law enforcement authorities to trace the culprits behind the recent attack. The microblog takes the opportunity to alert its users to ensure good password practice on Twitter and other social networking sites in a bid to safeguard their privacy and information.

"We encourage all users to take this opportunity to ensure that they are following good password hygiene, on Twitter and elsewhere on the Internet. Make sure you use a strong password - at least 10 (but more is better) characters and a mixture of upper- and lowercase letters, numbers, and symbols - that you are not using for any other accounts or sites. Using the same password for multiple online accounts significantly increases your odds of being compromised," asserts a blog post.

The blog post further educates users to disable Java on their browsers as the first step of security against unauthorised cyber intrusion:

"We also echo the advisory from the US Department of Homeland Security and security experts to encourage users to disable Java on their computers in their browsers. For instructions on how to disable Java, read this recent Slate article," adds the blog post.

This is not the first instance of hackers breaching security of Twitter systems and gaining access to private user information. As Reuters notes, Twitter had earlier signed a consent decree with the Federal Trade Commission in 2010, which had asked the company to undergo independent privacy reviews for 10 years for failing to safeguard users' privacy and personal data.