The hackers had successfully compromised Malawi’s domain registrar website(.mw). Attackers alter the DNS records of the affected websites, pointing the domain names to their own server having the deface page in it.
Domain Name System poisoning, the attack used by the hackers. It is also called DNS spoofing, is when an attacker is able to redirect a victim to different website than the address that he types into his browser.
You can check the mirrors of defaced website in zoneH. In the time of writing, domains are pointed back to its original web servers and all running well.