-4640 Union All Select Null,null,null,null,'qbqvq'||'lbznmmwdachxaypteqetdoupxsqdsedwqcwkldne'||'qqbqq',null,null,null,null-- Exgp →

: The payload concatenates (using || ) three strings. Canary Strings : qbqvq and qqbqq are "canaries" or markers.

Are you seeing this in your or during a security audit ? : The payload concatenates (using || ) three strings

: Scanners look for the unique middle string ( LBzNMMwda... ) surrounded by these markers in the server's response. If it appears, the vulnerability is confirmed. -- ExGP : : The payload concatenates (using || ) three strings