{keyword}' Union All Select Null,null,null,null,null,null,null,null From Msysaccessobjects-- Udhz -

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

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]. This is the gold standard

Comments out the rest of the original query so it doesn't cause a syntax error [1, 5]. How to Prevent It: Attackers use NULL to figure out how many

Sources:[1] microsoft.com[2] portswigger.net[3] geeksforgeeks.org[4] sqlinjection.net[5] owasp.org[6] owasp.org Only allow the types of characters you expect (e

These can often detect and block common patterns like UNION ALL SELECT before they reach your server.

Only allow the types of characters you expect (e.g., numbers for an ID field).

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].