Zoho ManageEngine OpManager before 12.3 Build 123196 does not require authentication for /oputilsServlet requests, as demonstrated by a /oputilsServlet?action=getAPIKey request that can be leveraged against Firewall Analyzer to add an admin user via /api/json/v2/admin/addUser or conduct a SQL Injection attack via the /api/json/device/setManaged name parameter.