I have had a problem with a 3rd party app that I have authorized to post my blog post automatically to my Twitter and LinkedIn account. My problem was that I forgot which app did it, as I have a habit of signing up to new 3rd party apps to check them and I sign up normally with a social network app like twitter or Facebook as they are easier to remember than having unique passwords for each new app sign up.
How do you check which app you used to authorize against Google, Twitter, Facebook, and LinkedIn, for me I had to go to each one to check account & app settings, these are the steps and links to each which hopefully will make it easier for you to check your apps. It’s a good practice that you do a check of your settings at least once a month.
When you revoke access and you want to use that app again, you will need to re-authorize an app the next time you log in from that app.
To revoke 3rd party app access to your Twitter account go to the Apps tab of your account settings.
Click the Revoke Access button next to the application.
Twitter help page for revoking an application.
To revoke 3rd party app access to your Gmail data go to Google Account settings.
Click on the application and on the right-side app info bar, click the Revoke Access button.
To revoke 3rd party app access to your Facebook account go to settings -> apps, select Logged in with Facebook.
Hover over the application you want to revoke access to and click the checkmark to delete.
To revoke 3rd party app access to your Linkedin account go to Privacy & Settings -> Account -> Partner & Third Party.
Click the checkbox next to the application and to complete the removal click the Remove button.
Linkedin Account Settings Authorized External Applications LinkedIn