Block by useragent or empty referer

Question

A stranger bot (GbPlugin) is codifying the urls of the images and causing error 404.
I tried to block the bot without success with this in the bottom of my .htaccess, bu

Answer 1

Here's what you can put in your .htacces file

Options +FollowSymlinks  
RewriteEngine On  
RewriteBase /  
SetEnvIfNoCase Referer "^$" bad_user
SetEnvIfNoCase User-Agent "^GbPlugin" bad_user
SetEnvIfNoCase User-Agent "^Wget" bad_user
SetEnvIfNoCase User-Agent "^EmailSiphon" bad_user
SetEnvIfNoCase User-Agent "^EmailWolf" bad_user
SetEnvIfNoCase User-Agent "^libwww-perl" bad_user
Deny from env=bad_user

This will return:

HTTP request sent, awaiting response... 403 Forbidden
2011-09-10 11:15:48 ERROR 403: Forbidden.

Answer 2

May I recommend this method:

Put this is .htaccess in root of your site.

ErrorDocument 503 "Your connection was refused"
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} ^(Mozilla.*537.36|Mozilla.*UCBrowser\/9.3.1.344)$ [NC]
RewriteRule .* - [R=503,L]

Where

^(Mozilla.*537.36|Mozilla.*UCBrowser\/9.3.1.344)$

are the two useragents I wanted to block in this example case.

You can use regex so a useragent like

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0

could be

Mozilla.*Firefox\/40.0

^means match from beginning and $ to the end so you could block just one useragent with:

ErrorDocument 503 "Your connection was refused"
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} ^Mozilla.*Firefox\/40.0$ [NC]
RewriteRule .* - [R=503,L]

Or add several using the | character to separate them inside ( and ) like in the first example.

RewriteCond %{HTTP_USER_AGENT} ^(Mozilla.*537.36|Mozilla.*UCBrowser\/9.3.1.344)$ [NC]

You can test it by putting your useragent in the code and then try to access the site. http://whatsmyuseragent.com/

Answer 3

To block empty referers, you can use the following Rule :

RewriteEngine on

RewriteCond %{HTTP_REFERER} ^$
RewriteRule ^ - [F,L]

This will forbid all requests to your site if HTTP_REFERER value is empty ^$ .

To block user agents, you can use

RewriteEngine on

RewriteCond %{HTTP_USER_AGENT} opera|firebox|foo|bar [NC]
RewriteRule ^ - [F,L]

This will forbid all requests to your site if HTTP_USER_AGENT matches the Condition pattern.