Last October, multiple subdomains of DENR from Region 1 to Region 11 were attacked by hackers from Indonesia.
The defacement was mirrored to Zone-H, an archive of defaced websites.
The hackers slammed the website for having weak security.
Web defacement is typically done by hackers who break into a web server and replace the hosted website with one of their own. Using techniques such as Remote Code Execution, SQL Injection, Cross Site Scripting etc. Common targets of defacement are religious websites, government websites, bank websites and corporate websites.
Earlier this month a website of the Office of the Solicitor General was also defaced.