If a service notifies you of a breach, change your password to something unique and strong. Do not reuse this password on other sites.
If you suspect your credentials might be in such a list, security experts from Norton and Avast recommend the following: 1,5M COMBOLIST GMAIL (TARGERED GAMING).txt
Compromised accounts are often used to send further phishing emails to the account owner’s contacts to spread malware. Steps to take if you are concerned If a service notifies you of a breach,