That string is a classic example of a attack payload [1]. Specifically, it's designed to probe or exploit an Access database (indicated by MSysAccessObjects ) [2, 3].
If successful, this allows someone to extract hidden information from a database, bypass logins, or see the internal structure of the site's data [1, 2]. If you see this in your website logs, it means a bot or a user is actively scanning your site for vulnerabilities. That string is a classic example of a attack payload [1]
: This targets a system table in Microsoft Access that contains information about database objects [2, 3]. 3]. If successful