How Can You Tell If Your Twitter Account Was Hacked?by David Weedmark
In one 2013 incident alone, about 250,000 Twitter accounts were compromised when someone broke into Twitter's database. While such massive exploitations are uncommon, hackers routinely break into accounts every day. Often, the account owner does not even notice for days or even weeks. Once you know what to look for, you can take measures to ensure you get back control of your account and take precautions to minimize the chance that it happens again.
Strange Activity on Your Account
If your Twitter account starts displaying bizarre activity, your account has likely been hacked. This includes direct messages (DMs) you didn't send and tweets you didn't post. Another warning sign of a hacked account is if it follows, unfollows or blocks people by itself. Unless you check your sent DMs, or scan through your own profile page, you might not notice these symptoms. The first clue may be messages or tweets from other people accusing you of spam, or followers beginning to unfollow you or block you. If people start reacting strangely, check your tweet history and DMs to make sure your account isn't causing the problem.
You Can't Log In
Once a hacker gets into your Twitter account, he's then in a position to change your password, username, contact email address and your profile information. If you find you can no longer log in to your own Twitter account, there's a good chance you have been hacked. If the email address you use for Twitter has been changed, you should find a notification email from Twitter in your Inbox or Spam folder indicating that this was requested. If Twitter suspects you have been hacked, it may reset your password for you and send you a notification to this effect. Another point of entry for a hacker can be any Twitter clients you use to manage your account, like TweetDeck or Hootsuite or even Facebook. If someone hacks into one of your Twitter client accounts, they can use it to access your Twitter account.
What to Do
If you suspect you have been hacked, change your Twitter password immediately and the passwords you use on any Twitter clients. If you can't change your password, contact Twitter support (see Resources for the link) and ask for a password reset to be sent to your email address. If your email address was changed, you will have to send Twitter a support request and tell them your account was hacked. In this case, Twitter requires your account name, original email address and information about when you last had access to your account.
Using a strong password and keeping it private is just the first step in ensuring your Twitter account doesn't get hacked. A common way hackers can get to your account is through the third-party apps you have authorized to access Twitter on your behalf. If the app is hacked, the hacker has access to your account through that app. Sometimes developers lose interest in the apps they created and no longer update their security systems, making them vulnerable to hackers. You should review the apps you have allowed to access your account on a regular basis and revoke access to those you don't use or don't recognize. To see these apps and revoke access, click the "Apps" option on your Twitter Settings page.