Block specific User Agent

[epodboj Profile]

I really can't find a solution, can someone pleas tell me how to block the following specific user agent exactly via isapi rewrite 3.0?

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0

I tried so many ways but it doesnt seem to work...

Please help!

[Anton]

Hello,

The config should be:

RewriteBase /
RewriteCond %{HTTP_USER_AGENT} Mozilla/5\.0 [NC]
RewriteRule .? - [F]