No one should be surprised nowadays when a site gets hacked. Even sites that you would expect would have an extremely high level of security are vulnerable, as shown by the hacking today of the United Nations official website.
Slogans accusing the US and Israel of killing children
appeared on the pages reserved for statements from UN Secretary General
Other pages on the site were also breached by the group, who described their actions as a "cyberprotest".
The UN only took sections down for "maintenance;" most of the site remained available. However, at the time of this writing the Secretary General's page was still being repaired.