{keyword}' Union All Select Null,null,null,null,null,null,null,null From Msysaccessobjects-- Udhz (LIMITED · CHEAT SHEET)

The best way to stop these attacks is to never "glue" user input directly into your database queries. Instead, use:

Matches the number of columns in the original table. Attackers use NULL to figure out how many columns they need to match without causing a data type error [2, 3]. The best way to stop these attacks is

A system table in Access that contains information about database objects. If successful, the attacker can see if they have access to system metadata [1, 4]. A system table in Access that contains information

This is the gold standard. It treats user input as literal text, not executable code [6]. It treats user input as literal text, not

It looks like you’ve included a SQL injection payload in your request. This specific string is designed to test for vulnerabilities in a database by attempting to "union" (combine) your query results with data from a system table—in this case, MSysAccessObjects , which is specific to [1, 2, 4].