Extractvalue(1,concat(char(126),md5(1729888217))) Review

: Use a WAF to detect and block common SQL injection patterns like extractvalue and concat .

: This joins the tilde with the MD5 hash (e.g., ~2336333435343461... ).

If the application is vulnerable, the database will return an error message similar to: XPATH syntax error: '~23363334353434613337613564653531'

: This generates a unique MD5 hash ( 23363334353434613337613564653531 ). Attackers use a random number like this to confirm that the output they see in the error message is indeed coming from the database and isn't just a static page. char(126) : This represents the tilde character ( ~ ).