The Security Token Service must not enable support for TRACE requests.
"Trace" is a technique for a user to request internal information about Tomcat. This is useful during product development but should not be enabled in production. Allowing an attacker to conduct a Trace operation against the Security Token Service will expose information that would be useful to perform a more targeted attack. The Security Token Service provides the "allowTrace" parameter as a means to disable responding to Trace requests.