SQL Injection is a way attackers trick a website into running their database commands. Instead of treating a form field (like “username”) as plain text, a vulnerable site stuffs that text straight into a database query. If an attacker types special characters and SQL words, the site may run them - letting the attacker peek at tables, change data, or even delete it. Think of it as slipping a second instruction into a message meant for the database. Well-built apps block this; rushed ones sometimes don’t.
A single SQLi hole can expose logins, emails, payment info - or let someone take over accounts and wipe records. Breaches from SQLi often lead to identity theft and big service outages.
Find input: attacker tests fields/URLs for errors or odd responses.
Inject: adds SQL pieces (quotes, OR/AND, UNION, etc.) to change the query.
Extract/modify: dumps tables, changes passwords, or deletes rows.
Pivot: uses the database foothold to move deeper into the app or network.
Weird database error messages shown to users (with “SQL” or table names).
Sudden spikes in requests with quotes, UNION, or odd parameters.
Unexplained data changes or new admin accounts.
WAF/EDR alerts about injection patterns in web traffic.
Parameterized queries (prepared statements): never build SQL by string-concatenating user input.
ORM/Query builders: use safe APIs that bind values for you.
Input handling: validate types/lengths; reject unexpected characters where possible.
Least privilege: app DB user should only have the permissions it needs.
WAF & monitoring: block common SQLi patterns and alert on anomalies.
Tests: run automated scanners and add unit/integration tests for SQLi cases.