Apache Wicket: hidden form buttons can still be submitted by crafted requests

Missing authorization in Apache Wicket.

org.apache.wicket.markup.html.form.Form resolves the component that submitted a form from the request parameters in Form#onRequest() and passes the result directly to Form#onFormSubmitted(IFormSubmitter). The check that the submitting component is visible and enabled in its hierarchy runs only when onFormSubmitted() is given no submitter, so it no longer runs for an ordinary form submission, and it is the only point at which Wicket verifies that the application actually offered the named control to the caller. Form#findSubmitter() matches on the request parameter name alone and applies no visibility or enablement filter, and the request handler checks only the form itself, which is visible and enabled. A request that names a submit button the application withheld therefore reaches that button's onSubmit() and onAfterSubmit(), and its onError() when form validation fails; where the button sets setDefaultFormProcessing(false) it reaches onSubmit() and onAfterSubmit() without any form validation.

An application is affected where a form submitting component, such as a Button or a SubmitLink, is unavailable to the caller while the enclosing form remains available. How the component was made unavailable does not matter: the component's own setVisible(false), setEnabled(false) or setVisibilityAllowed(false), an overridden isVisible() or isEnabled(), an invisible or disabled parent container anywhere above it, and a RENDER or ENABLE denial from IAuthorizationStrategy — for example through MetaDataRoleAuthorizationStrategy or the AuthorizeAction annotation — are all enforced by that one check, and all of them are bypassed. A component that renders as disabled carries its own input name in the markup the caller already holds. Submissions made through AjaxFormSubmitBehavior, and therefore through AjaxButton and AjaxSubmitLink, are not affected: those are invoked as a behaviour on the button itself, the behaviour's invocation is authorized against that button, and the non-Ajax callbacks of those two classes do nothing. Restrictions applied to the form or to the page rather than to the submitting component are unaffected.

The 9.x and 8.x release lines, and the unsupported lines before them, are not affected; the behaviour was introduced in 10.3.0.

This issue affects Apache Wicket: from 10.3.0 through 10.11.0. Users are recommended to upgrade to version 10.12.0, which fixes the issue.