You can control whether third-party apps can access your account using app passwords. For example, the password that you create for your email client will not allow access to your Yandex.Disk and no application password will provide access to the management of your account.
You can create app passwords on the access management page. Just enable the app passwords option (if two-factor authentication is enabled, app passwords are mandatory and they can't be disabled).
You will need to create a separate password for each third-party application or program that requires you to enter your Yandex password. These include:
email clients (Mozilla Thunderbird, Microsoft Outlook, The Bat!, etc.);
WebDAV client for Yandex.Disk
CalDAV client for Yandex.Calendar
Jabber client (Pidgin, Adium, etc.);
mail importers for other mail services (Mail.ru, Gmail, Outlook.com and others)
To create an app password:
Go to the access management page.
Enable the App passwords option if you haven't already (the switcher won't display if you haven't enabled two-factor authentication).
Select the Yandex service accessed by the application.
Enter the name of the application that you are creating a password for. The password will be shown with this name in the list.
Click the Create password button. The app password will appear in a pop-up window.
Resetting application passwords
All application passwords that you created get reset in the following cases:
You change a password (with two-factor authentication disabled)
You enable or disable two-factor authentication
You restore access to your account yourself or with the help of our Support staff
You clicked Log out on all devices on the main Yandex.Passport page.
Every app password you use must be re-generated following any of these events.