Description
The Liferay JSON implementation do not check if a user that call a method on a serviceClass is disabled. Usually the default administrator user, test@liferay.com, is used to create a new administrator and disabled without to change the default password, so it is possible to use it to execute JSON API calls.
Remediation
Upgrade to the latest version of Liferay.
References
Related Vulnerabilities
Jenkins Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2018-1999046)
PHP Numeric Errors Vulnerability (CVE-2014-2020)
Python Improper Input Validation Vulnerability (CVE-2013-7338)
MediaWiki Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2017-0361)