{keyword}' - Union All Select Null-- Fhda

While "FHDA" likely refers to a specific target or internal tracking tag used by a security researcher or a tool, the string itself is a classic example of an . To prevent such attacks, developers should always use parameterized queries (prepared statements) rather than building queries with raw user input.

The UNION ALL command is used to combine the results of two different SQL queries into a single result set. Attackers use this to trick a database into returning sensitive information (like usernames, passwords, or configuration data) that the user was never intended to see. 3. SELECT NULL {KEYWORD}' UNION ALL SELECT NULL-- FHDA

The initial ' (single quote) is used to "break out" of a predefined data field in a website's code. If the application isn't properly sanitizing inputs, this quote tells the database that the original command has ended and a new one is beginning. 2. The UNION ALL Operator While "FHDA" likely refers to a specific target

The -- (double dash) is the SQL syntax for a comment. Everything following these dashes is ignored by the database. This is used to "comment out" the rest of the original, legitimate code (like a closing quote or a WHERE clause) that would otherwise cause a syntax error and crash the attack. Attackers use this to trick a database into

The SELECT NULL part is often a "probe." For a UNION attack to work, the second query must have the exact same number of columns as the first. Attackers will add NULL values one by one (e.g., SELECT NULL, NULL-- ) until the page stops returning an error, which reveals how many columns are in the targeted table. 4. Commenting Out ( -- )