Why this site was been defaced?

Re: -https://register.riuf.ro/

Security Checks for https://register.riuf.ro/ (2) Vulnerabilities can be uncovered more easily X-Powered-By header exposed Server information header exposed (4) Susceptible to man-in-the-middle attacks HTTP Strict Transport Security (HSTS) not enforced HSTS header does not contain max-age HSTS header does not contain includeSubDomains HSTS header not prepared for preload list inclusion Unnecessary open ports Administration ports open

F-grade website status and recommendations: https://observatory.mozilla.org/analyze/register.riuf.ro
See: https://aw-snap.info/file-viewer/?protocol=secure&tgt=register.riuf.ro&ref_sel=GSP2&ua_sel=ff&fs=1

Response 0.0.0.0 , re: https://urlquery.net/report/d2553110-675c-4ee9-95fe-bcaa0b408d41

polonus (volunteer website security analyst and website error-hunter)