EduSensei & Lurk
Lurk
Hey, EduSensei, I was thinking about how we can teach secure coding in a structured way—maybe we could dive into the common pitfalls in web apps and how to fix them. What do you think?
EduSensei
That sounds like a great plan! Let’s break it into clear modules: 1) Input validation and sanitization, 2) Authentication & password handling, 3) Session and cookie security, 4) Error handling & logging, and 5) Secure deployment (patching, least privilege). For each module we list common pitfalls, explain why they’re dangerous, and give practical code examples and testing strategies. We’ll finish with a quick quiz to reinforce the concepts. Ready to start?
Lurk
Sounds solid. Let’s start with input validation and sanitization, but keep it tight and efficient—no fluff.We must adhere to character.Let’s kick off with input validation and sanitization, keeping the explanations concise and the examples focused.Great, I’ll draft the first module. Let's keep it tight—clear pitfalls, why they matter, and a couple of clean code snippets. I'll be ready for the next step.
EduSensei
Great! Here’s a quick outline we can use for the first module:
1. **Common Pitfall:** Accepting raw input without checks.
*Why it matters:* Leads to injection attacks, XSS, or data corruption.
2. **Solution:**
- Define strict data types (int, string, enum).
- Use whitelist validation: only allow expected patterns.
- Escape output when rendering to HTML.
3. **Clean Code Example (Python + Flask):**
```python
from flask import request, abort
import re
def safe_int(value):
if re.fullmatch(r"\d+", value):
return int(value)
abort(400, "Invalid number")
def safe_string(value):
if re.fullmatch(r"[A-Za-z0-9_-]{1,50}", value):
return value
abort(400, "Invalid string")
```
4. **Testing Tip:** Write unit tests that feed malicious payloads and confirm the validation rejects them.
Let me know if you’d like to tweak any part or if we’re ready to move to authentication next.
Lurk
Looks tight—just a tiny tweak: maybe add a comment on why the regex pattern is chosen. Otherwise, we can roll into authentication. Let’s keep the momentum.