Severity: Important

Vendor:
The Apache Software Foundation

Versions Affected:
Apache Wicket 1.4.x and 1.5.x

Description:
It is possible to view the content of any file of a web application by
using an Url to a Wicket resource which resolves to a 'null' package.
With such a Url the attacker can request the content of any file by specifying
its relative path, i.e. the attacker must know the file name to be able to
request it.

Mitigation:
Setup a custom org.apache.wicket.markup.html.IPackageResourceGuard that provides
a whitelist of allowed resources.
Since versions 1.4.20 and 1.5.5 Apache Wicket uses by default
org.apache.wicket.markup.html.SecurePackageResourceGuard with a preconfigured
list of allowed file extensions.
Either setup SecurePackageResourceGuard with code like:

MyApp#init() {
  ...
  SecurePackageResourceGuard guard = new SecurePackageResourceGuard();
  guard.addPattern(...);
  guard.addPattern(...);
  ...
  getResourceSettings().setPackageResourceGuard(guard);
}

or upgrade to Apache Wicket 1.4.20 or 1.5.5.

Credit:
This issue was discovered by Sebastian van Erk.

Apache Wicket Team