As said elsewhere or maybe here it is the issue of vbulletin not supporting older software to which this site runs on. Google vbulletin hack or vbulletin security hole. Plugs have nothing to do with it.
As for the urls yeah someone aught to report all those crud tumblr ones and all the ones that randomly show up. Also note do not search sfm via google or a search engine as that will send you to a redirect of some sort which is a common hack as well.

As mentioned I would use a script or adblocker that can block all 3rd party scripts or frames. And can selectively block or allow specific elements or scripts. In that image you can see the red on the right in 3rd party means anything no matter what if it does not contain the sfm url on it it wont run.
Also note adblockers do not necessarily block hacks bad scripts etc just adverts. Most have subscriptions that allow you to add exploits hacks etc or bad urls. I would technically use a hosts file to block those as well. Known evil urls and stop them loading on the system from any application. Like all those damned adobe hive/botnet urls and ips.
To note in the past I recommended ABP but that app starts to gloat like mad and does not always block frames or elements you select. Worse is if you use a tab manager or other tool to load last tabs or windows from the last session ABP will not be in effect on any pages loading in focus or behind other tabs. This is a new behavior for it either it is something Firefox broke or it is ABP playing games or a limitation. So far Ublock Origin is the cleanest and fastest evcen with my HUGE list of ABP custom blocks and subscribing to a tonne of ublock subs. Onbly complain is the pop ups and element blocking is cludgy vs ABPs add ins.
Heh that list of crappy Russian image sites has grown.
Code:
</head>
<body>
<div style="text-indent:-9999px; position:fixed">
<a href="http://asuszenfone2.tumblr.com/">asuszenfone</a>
<a href="http://izlehdfilm.tumblr.com/">film</a>
<a href="https://guncelbegenihileleriinstagram.tumblr.com/">güncel beğeni</a>
<a href="https://guncelinstagramhileleri2017.tumblr.com/">güncel instagram</a>
<a href="https://guncelinstagramtakipciyollari.tumblr.com/">instagram takipçi</a>
<a href="http://guncelhaberlerbugun.tumblr.com/">haberler</a>
<a href="http://guncelhaberlerturkiye.tumblr.com/">güncel haberler</a>
<a href="https://guncelinstagramtakiphileleri2017.tumblr.com/">instagram takip hileleri</a>
<a href="http://haberlerioku.tumblr.com/">haberleri</a>
<a href="https://instabayim.tumblr.com/">instabayim beğeni</a>
<a href="https://instabayimbegeni.tumblr.com/">instabayim</a>
<a href="https://instagram200begenihilesi.tumblr.com/">instagram 200</a>
<a href="https://instagram200takipcihilesi.tumblr.com/">instagram 200 takipçi</a>
<a href="https://instagram200yorumhilesi.tumblr.com/">instagram 200 yorum</a>
<a href="https://instagrambegenihilesiucretsiz.tumblr.com/">instagram beğeni hilesi</a>
<a href="https://instagrambegenikasmahilesi.tumblr.com/">instagram beğeni kasma</a>
<a href="https://instagramgiris.tumblr.com/">instagram</a>
<a href="https://instagramtakipciarttirma.tumblr.com/">instagram takipçi</a>
<a href="https://instagramtakipcikazan.tumblr.com/">instagram takipçi</a>
<a href="http://lgg5fiyati.tumblr.com/">lg5</a>
<a href="http://samsungnote7.tumblr.com/">samsungnote</a>
<a href="http://sondakikaturkiye.tumblr.com/">sondakika</a>
<a href="http://sonyxperiaz5.tumblr.com/">sony</a>
<a href="https://takipcigondermearaci.tumblr.com/">takipçi</a>
<a href="https://takipcigondermesitesi.tumblr.com/">takipçi gönderme</a>
<a href="http://turkiyesondakika.tumblr.com/">son dakika türkiye</a>
<a href="http://diziizleyabanci.tumblr.com/">dizi</a>
<a href="http://yenihaberleristanbul.tumblr.com/">haberler</a>
<a href="https://instagramgunceltakipcikasma.tumblr.com/">instagram güncel takipçi</a>
<a href="https://ucretsizinstagramtakipcikas.tumblr.com/">ücretsiz instagram takipçi</a>
<a href="https://ucretsizinstagram500takip.tumblr.com/">ücretsiz instagram 500</a>
<a href="https://ucretsizinstagramhileler.tumblr.com/">ücretsiz instagram</a>
<a href="https://bedavainstagramtakipci.tumblr.com/">bedava instagram</a>
<a href="https://ucretsizguncelinstagramtakip.tumblr.com/">ücretsiz güncel instagram</a>
<a href="https://guncelinstagramhilelerikasma.tumblr.com/">güncel instagram hileleri</a>
<a href="https://instagramtakipcikasmaucretsiz.tumblr.com/">instagram takipçi</a>
<a href="https://ucretsiztakipcihileinstagram.tumblr.com/">ücretsiz takipçi</a>
<a href="https://ucretsizinstagramhileleriguncel.tumblr.com/">ücretsiz instagram</a>
<a href="https://ucretsizinstagramtakipcibegeni.tumblr.com/">takipçi ve beğeni</a>
<a href="https://ucretsizinstagramhileleri.tumblr.com/">ücretsiz instagram</a>
<a href="https://ucretsizinstagramtakipcihile.tumblr.com/">takipçi</a>
<a href="https://ucretsizinstagramtakipci.tumblr.com/">instagram</a>
<a href="https://instagramtakipcikasmasitleri.tumblr.com/">instagram</a>
<a href="https://ucretsizinstagramtakipcisite.tumblr.com/">instagram takipçi</a>
<a href="https://ucretsizinstagramtakipkasma.tumblr.com/">instagram takip</a>
<a href="https://ucretsizinstagramtakipci1k.tumblr.com/">ilk ücretsiz</a>
<a href="https://ucretsiztakipcikasmasiteniz.tumblr.com/">ücretsiz takipçi kasma</a>
<a href="https://instagramucretsiz1ktakipci.tumblr.com/">instagram ücretsiz</a>
<a href="https://instagram1000takipcikazan.tumblr.com/">instagram 1000</a>
<a href="https://instagram500takipcihileleri.tumblr.com/">instagram 500</a>
<a href="https://instagramfenomentakipci.tumblr.com/">instagram</a>
<a href="https://instagramucretsizbegenihilesi.tumblr.com/">instagram ücretsiz</a>
<a href="https://instagramtakipcikazanmahile.tumblr.com/">instagram takipçi</a>
<a href="https://instagramfenomenyollari.tumblr.com/">instagram fenomen</a>
<a href="https://instagramguncelbegenihile.tumblr.com/">instagram güncel</a>
<a href="https://instagramgunceltakipci.tumblr.com/">instagram güncel</a>
<a href="https://instagramtakibetakiphilesi.tumblr.com/">instagram takip</a>
<a href="https://instagramtakipciucretsiz.tumblr.com/">instagram takipçi ücretsiz</a>
<a href="https://instagramtakipcikasmayollar.tumblr.com/">instagram takipçi</a>
<a href="https://instagramtakipciarttirmasite.tumblr.com/">instagram takipçi</a>
<a href="https://instagramtakipciucretsizkasma.tumblr.com/">instagram takipçi ücretsiz</a>
<a href="https://instagramtakipcikasalim.tumblr.com/">hemen takipçi</a>
<a href="https://instagramucretsizgunceltakipci.tumblr.com/">güncel instagram ücretsiz</a>
<a href="https://instagramtakipci.tumblr.com/">instagram takipçi</a>
<a href="https://instagramtakipcinasilkasilir.tumblr.com/">instagram takipçi nasıl</a>
<a href="https://instagrambegenihileguncel.tumblr.com/">instagram beğeni</a>
<a href="https://instagramtakipcinasilarrtir.tumblr.com/">instagram takipçi nasıl</a>
<a href="https://instagramtakipcihileleriguncel.tumblr.com/">instagram takipçi</a>
<a href="https://instagramtakipcikasmahile.tumblr.com/">instagram takipçi kasma</a>
<a href="https://instagramucretsiztakipci.tumblr.com/">instagram ücretsiz</a>
<a href="http://internetgazetesi.tumblr.com/">internet gazetesi</a>
<a href="http://iphone8fiyati.tumblr.com/">iphone 8</a>
</div>
dunno what that crap does short of exist in the code. It is only on the site's root so shrug.
Bookmarks