The US Federal Trade Commission (FTC) has criticised Twitter's lax internal security procedures, which enabled hackers to post fake statements from the accounts of US President Barack Obama and others.
The FTC found that Twitter did not restrict administrative access to certain computers, prohibit simple passwords for administrators, or require regular password changes, according to a report in the Financial Times.
In January 2009 a hacker used an automated password-guessing tool to crack the management account of a Twitter employee, the FTC revealed.
The hacker used that access to reset passwords on regular accounts, including Obama's, and posted the new passwords on the web.
Other people then used those passwords to send phoney messages from Obama's account and those of eight other people.