Understand how WAS handles Plugin Headers....default true...
The trusted custom property enables the application server to use inbound private headers from the web server plug-in. These inbound private headers notify the application server about the connection to the web server. When you set the custom property to true, the application server uses the asserted information on the client certificates. These client certificates are used by the end user to connect to the web server and establish the client information, which is treated as the certificate for the end user. Then, the application server uses the certificate information for authentication purposes when client certificate authentication is used or when the application code accesses the javax.net.ssl.peer_certificates certificates. Because this information is asserted, it is insecure and potentially vulnerable to an attacker that is able to connect directly to the application server and bypass the web server.
Important: If you allow direct connections to the application server and use client certificates, you must set this custom property to false.