The Hacker found and exploited SQL Injection flaw in the website and managed to upload the deface page with the deface message.
Mirror of the Hacked Website:
As its an official embassy website, its not known, whether this site contained classified diplomat data or hacker accessed to sensitive data if it contains. But its clear, hacker had accessed to the database and defaced the website.
The message left by the hacker on the deface page can be found below:
Website has been Hacked coz Security Sucks..Like Your Dirty Face..Ha ha ha..South Sudan the New shit..Long Live Yemen