If your account has been compromised but you're still able to log in, this page will help you secure your account and stop unwanted behaviors. If you can't log in to your account, please see this troubleshooting article.
Have you:
1. Change your password
Please change your password immediately from the Password tab in settings. Please select a strong password you haven't used before. If you can't log in to your account, please see this troubleshooting page.
2. Revoke connections to third-party applications
While logged in, visit Apps in your settings. Revoke access for any third-party application that you don't recognize.
3. Update your password in your trusted third-party applications
If a trusted external application uses your Twitter password, be sure to update your password in that application. Otherwise, you may be temporarily locked out of your account due to failed login attempts.
Your account should now be secure, and you shouldn't see the unexpected account behaviors moving forward. If you're still experiencing issues, please file a Support request for assistance.
If your account has been compromised, take these additional precautions:
Accounts may become compromised if you've entrusted your username and password to a malicious third-party application or website, if your Twitter account is vulnerable due to a weak password, if viruses or malware on your computer are collecting passwords, or if you're on a compromised network.
Unexpected updates don't always mean that your account was hacked. Occasionally, a third-party application can have a bug that causes unexpected behavior. If you see strange behavior, changing your password and/or revoking connections will stop it, as the application will no longer have access to your account.
It's best to take action as soon as possible if updates are appearing in your account that you did not post or approve. You can find more information about account security on the Safe Tweeting help page.