public class ExUsernamePasswordAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

    @Override
    public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException {
        final String dbValue = request.getParameter("dbParam");
        request.getSession().setAttribute("dbValue", dbValue);

        return super.attemptAuthentication(request, response); 
    } 
}