-1" OR 5*5=25 or "vyHjdoKB"="

That string looks like a simple SQL injection payload. It’s trying to break out of a quoted string and inject an OR condition that is always true (5*5=25), which can turn a restrictive WHERE clause into something tautological and leak data or bypass checks.

What it’s doing in theory

• The -1" attempts to close an existing quoted string.
• OR 5*5=25 is a condition that evaluates to true.
• The rest (or "vyHjdoKB"=") hints at another string comparison, continuing the attempt to keep the overall condition true.

Why this matters in exams

• It tests understanding of how vulnerable queries can be built by string concatenation.
• It checks knowledge of how tautologies can defeat authentication or filtering if inputs aren’t properly handled.

Defensive practices (recommended)

• Use parameterized queries / prepared statements (never concatenate user input into SQL).
• Validate and sanitize inputs, but rely on parameterization as the primary defense.
• Use least-privilege database accounts (no access beyond what’s necessary).
• Prefer ORMs or safe abstractions that build queries with parameters.
• If you must escape, use proper escaping for the specific database, but this is error-prone compared to parameterization.
• Consider input length limitations and white-list allowed values for certain fields.

Quick examples

• Unsafe (vulnerable): SELECT * FROM users WHERE username = 'user_input' AND password = 'pass_input'; // If user_input or pass_input contains strange characters, it might be exploited.

• Safe: Using parameters (example in Python with psycopg2) cursor.execute("SELECT * FROM users WHERE username=%s AND password=%s", (username, password))

What would you like next?

• A more detailed safety-focused example in a specific language?
• A practice exercise identifying vulnerable vs. safe patterns?
• An explanation of how to test a codebase for SQL injection safely?