Insecure Default Initialization In Liferay Portal
In Liferay Portal 7.3.0 and earlier, and Liferay DXP 7.2 and earlier the default configuration does not require users to verify their email address, which allows remote attackers to create accounts using fake email addresses or email addresses which they don't control. The portal property
company.security.strangers.verify should be set to true.
All versions starting from 7.0.0 before 7.3.1
Upgrade to version 7.3.1 or above.