This is a final "always true" statement used to ensure the rest of the original, legitimate SQL query doesn't break the injection. What is the Goal?
CHR(100)||CHR(85)||CHR(102)||CHR(83) translates to the string "dUfS" .The code asks the database: "Does dUfS equal dUfS?" Since this is always true, the database will process the request without an error. This is a final "always true" statement used
The payload uses AND statements. For the database to return a result, the conditions following the AND must be true. This is a final "always true" statement used
The 'KEYWORD' starts by closing a legitimate search or input field with a single quote. This allows the attacker to append their own logic. This is a final "always true" statement used