Error pages of your website like 404 not found, 403 access forbidden pages contains server signature i.e. server version number, operating system etc., such information could be misused by attackers. Mostly servers or operating systems has some loopholes that could be misused. One with these details can paralyzed your system with focused attacks. Unknowingly or knowingly, revealing Information about your server, hosting operating system, PHP versions is a potential threats and security risk for you website which are hosted on such web servers, it shows your system’s vulnerability to attackers.
As a webmaster, you can disable your server signature by htaccess file. Put following line in your htaccess file in your root directory: