Information
Disable directory browsing for your web applications. Directory browsing automatically list the contents of directories that do not have an index page or welcome page present.
Directory browsing enables the web applications to expose the file names in the application.
Solution
Add the directoryBrowsingEnabled attribute on the webContainer element in ${server.config.dir}/configDropins/overrides/*.xml and set it to false
<webContainer directoryBrowsingEnabled="false"/>
If directory browsing is set at the application level, update the webApplication elements or ibm-web-ext files.