Web Hacking for Pentesters: SQL Injection

Overview

SQL injection remains dangerous wherever untrusted input is concatenated into database queries. Legacy modules, report builders, and “flexible filters” are frequent sources even in otherwise modern stacks.

This guide emphasizes detection mindset and remediation. Destructive testing against production is rarely appropriate—prove influence carefully within authorization.

What You Will Learn

• Locate likely query construction points

• Interpret differential and error-based signals responsibly

• Describe impact without overclaiming

• Push parameterized queries and least privilege

Where SQLi Still Hides

• Login, search, sort, and multi-filter endpoints

• Admin reports and CSV export builders

• Legacy stored procedures assembling dynamic SQL

• Second-order cases: stored input later used unsafely in a query

Authorized Testing Approach

Confirm the feature touches a database (latency, errors, feature behavior).

Look for differential responses and verbose DB errors in non-production first when possible.

Prefer the minimum evidence that demonstrates query influence.

Stop when impact is clear; do not extract sensitive datasets “to prove a point.”

Impact Framing

Impact depends on DB account privileges, exposed tables, and whether write/admin operations are possible.

Authentication bypass via injectable login queries can be critical—state prerequisites honestly.

Remediation

Use parameterized queries / prepared statements everywhere.

Apply least-privilege database roles per service.

Never return raw database errors to end users.

Add regression tests for the vulnerable parameter.

Conclusion

Use these techniques only on systems you are authorized to assess. SapiensHack focuses on practical methodology, clear evidence, and fixes teams can ship.

Related Reading

• Web Hacking for Pentesters: Cross-Site Scripting (XSS)

• Penetration Testing: Web Application Checklist (WAPT)

• Start Here: SapiensHack Learning Path