The operators of the service Kayo reached out to the security expert Troy Hunt to report the data and for further investigation. Kayo shared 755 files totaling 1.8GB.
According to Hunt, the data is typically taken from multiple data breaches and then combined into a single list to perform Credential stuffing attacks. The data is not related to Kayo.moe and the platform is not affected by any incidents.
The data also contains a number of files, some with partial credit card data, logs and some with Spotify details. While checking for Email, Hunt found 42M unique values Email Address 93% of them already exists in HIBP.
There was no single pattern for the breaches they appeared in and the only noteworthy thing that stood out was a high hit rate against numeric email address aliases from Facebook added Hunt.
— Troy Hunt (@troyhunt) September 13, 2018
These Credential stuffing attacks can be avoided by using a unique password for each service and change the passwords to all accounts at least once a month.
You can also strengthen your security by taking additional precautions such as moving to two-factor authentication. Don’t use the same password for multiple accounts, especially Internet banking and other accounts where money or sensitive information are involved.