This indicates an attack attempt against a Security Bypass vulnerability in D-link WebInterface.
The vulnerability is caused by a design issue when the vulnerable software handles a http request with xmlset_roodkcableoj28840ybtide User-Agent HTTP header. It allows a remote attacker to bypass authentication via a crafted http request.
System Compromise: Remote attacker can gain control of vulnerable systems.
Refer to the vendor's web site for suggested workaround.