This is a 'blind' sql injection attack. Tools like sqlmap make finding and exploiting sql injection very easy. sqlmap includes excellent support for blind sqli exploitation.
SQL injection is very common in our space which is WordPress. (I'm the Wordfence founder) There are over 40,000 plugins for WP and around 25k developers and writing PHP with a sqli vulnerability is really easy to do accidentally so it is super common.
SQL injection is very common in our space which is WordPress. (I'm the Wordfence founder) There are over 40,000 plugins for WP and around 25k developers and writing PHP with a sqli vulnerability is really easy to do accidentally so it is super common.