The account of Twitter's CEO Jacek Dorsey on his own portal is observed by over 4 million users. Yesterday most of them could have been very surprised, because 17 offensive tweets were sent from his account, among others indicating the presence of a bomb at Twitter headquarters. These messages were deleted quite quickly, and most people who read these tweets guessed that these tweets were not created by account's owner. This guess was correct, because during Friday evening hackers from Chuckling Squad hacked account of Twitter's managing director.
The most interesting topic related to hacking the Twitter CEO's profile is how group managed to access his account. Dorsey's account was protected by additional security, but it was bypassed in easy way. Group named Chuckling Squad admitting to the attack used a duplicate of SIM card obtained without the knowledge of Twitter director, and this information was confirmed by people associated with the Twitter portal. As you can see, even the best security can be broken, and really none of us can feel completely safe on the Internet.