This is something I came across on perishablepress.com was a way to help protect your website though the .htaccess file.
# 5G BLACKLIST/FIREWALL (2013)
# @ https://perishablepress.com/5g-blacklist-2013/
# 5G:[QUERY STRINGS]
RewriteEngine On
RewriteBase /
RewriteCond %{QUERY_STRING} ("|%22).*(<|>|%3) [NC,OR]
RewriteCond %{QUERY_STRING} (javascript:).*(;) [NC,OR]
RewriteCond %{QUERY_STRING} (<|%3C).*script.*(>|%3) [NC,OR]
RewriteCond %{QUERY_STRING} (\|../|`|='$|=%27$) [NC,OR]
RewriteCond %{QUERY_STRING} (;|'|"|%22).*(union|select|insert|drop|update|md5|benchmark|or|and|if) [NC,OR]
RewriteCond %{QUERY_STRING} (base64_encode|localhost|mosconfig) [NC,OR]
RewriteCond %{QUERY_STRING} (boot.ini|echo.*kae|etc/passwd) [NC,OR]
RewriteCond %{QUERY_STRING} (GLOBALS|REQUEST)(=|[|%) [NC]
RewriteRule .* - [F]
# 5G:[USER AGENTS]
# SetEnvIfNoCase User-Agent ^$ keep_out
SetEnvIfNoCase User-Agent (binlar|casper|cmsworldmap|comodo|diavol|dotbot|feedfinder|flicky|ia_archiver|kmccrew|nutch|planetwork|purebot|pycurl|skygrid|sucker|turnit|vikspider|zmeu) keep_out
Order Allow,Deny
Allow from all
Deny from env=keep_out
# 5G:[REQUEST STRINGS]
RedirectMatch 403 (https?|ftp|php)://
RedirectMatch 403 /(https?|ima|ucp)/
RedirectMatch 403 /(Permanent|Better)$
RedirectMatch 403 (=\'|=\%27|/\'/?|).css()$
RedirectMatch 403 (,|)+|/,/|{0}|(/(|...|+++|||\"\")
RedirectMatch 403 .(cgi|asp|aspx|cfg|dll|exe|jsp|mdb|sql|ini|rar)$
RedirectMatch 403 /(contac|fpw|install|pingserver|register).php$
RedirectMatch 403 (base64|crossdomain|localhost|wwwroot|e107_)
RedirectMatch 403 (eval(|_vti_|(null)|echo.*kae|config.xml)
RedirectMatch 403 .well-known/host-meta
RedirectMatch 403 /function.array-rand
RedirectMatch 403 );$(this).html(
RedirectMatch 403 proc/self/environ
RedirectMatch 403 msnbot.htm)._
RedirectMatch 403 /ref.outcontrol
RedirectMatch 403 com_cropimage
RedirectMatch 403 indonesia.htm
RedirectMatch 403 {$itemURL}
RedirectMatch 403 function()
RedirectMatch 403 labels.rdf
RedirectMatch 403 /playing.php
RedirectMatch 403 muieblackcat
# 5G:[REQUEST METHOD]
RewriteCond %{REQUEST_METHOD} ^(TRACE|TRACK)
RewriteRule .* - [F]
# 5G:[BAD IPS]
Order Allow,Deny
Allow from all
# uncomment/edit/repeat next line to block IPs
# Deny from 123.456.789