TL;DR
GitHub Copilot suggests code based on context from your files. It might suggest insecure patterns, hardcoded values, or code that looks secure but isn't. Always review suggestions before accepting, use .copilotignore to exclude sensitive files, and configure privacy settings in your organization. Copilot doesn't deploy code, so security depends on your review process.
How GitHub Copilot Works
Copilot runs in your editor (VS Code, JetBrains, etc.) and suggests code based on:
- Current file: What you're currently editing
- Open files: Other tabs open in your editor
- Comments and names: Function names, comments, variable names
- Training data: Patterns learned from public code
Security Risks with Copilot Suggestions
1. Insecure Code Patterns
Copilot learned from public code, which includes insecure examples:
// SQL injection risk
const query = `SELECT * FROM users WHERE id = ${userId}`;
// Use parameterized queries instead
const query = 'SELECT * FROM users WHERE id = $1';
const result = await client.query(query, [userId]);
2. Placeholder Secrets
Copilot often suggests code with placeholder values that look real:
// Copilot might suggest these "example" values
const API_KEY = "sk_test_abc123xyz";
const SECRET = "supersecretpassword123";
const DATABASE_URL = "postgres://admin:admin@localhost/db";
// Always replace with environment variables
const API_KEY = process.env.API_KEY;
const SECRET = process.env.SECRET;
const DATABASE_URL = process.env.DATABASE_URL;
Watch for: Suggestions that include strings starting with sk_, pk_, api_, or contain words like password, secret, token.
3. Missing Security Checks
Copilot focuses on functionality, not security:
// Copilot's suggestion (functional but insecure)
app.delete('/api/posts/:id', async (req, res) => {
await db.posts.delete(req.params.id);
res.json({ success: true });
});
// What you should add
app.delete('/api/posts/:id', authenticate, async (req, res) => {
const post = await db.posts.findOne(req.params.id);
if (post.authorId !== req.user.id) {
return res.status(403).json({ error: 'Not your post' });
}
await db.posts.delete(req.params.id);
res.json({ success: true });
});
Configuring Copilot for Security
Using .copilotignore
Exclude sensitive files from Copilot's context:
# Environment files
.env
.env.*
# Configuration with secrets
config/secrets.js
**/credentials.*
# Private keys
*.pem
*.key
# Internal/proprietary code
src/proprietary/
internal/
Organization Settings
For GitHub Copilot Business, admins can configure:
- Suggestions matching public code: Block suggestions that match public code exactly
- Allow/block by repository: Control which repos can use Copilot
- User telemetry: Configure what data is sent to GitHub
Reviewing Copilot Suggestions
Before Accepting a Suggestion
No hardcoded secrets, keys, or passwords
No SQL/NoSQL injection vulnerabilities
Input is validated before use
Authentication/authorization where needed
Error handling doesn't expose internal details
External calls use HTTPS
No eval() or similar dangerous functions
Best Practices for Secure Copilot Use
1. Use Descriptive Comments
Include security requirements in comments to get better suggestions:
// Create a login endpoint with:
// - Input validation for email and password
// - Bcrypt password comparison
// - Rate limiting (5 attempts per 15 min)
// - No sensitive data in error messages
async function login(req, res) {
// Copilot will suggest more secure code
}
2. Review Before Accepting
Don't blindly accept suggestions with Tab. Read them first.
3. Use Copilot Chat for Security
// In Copilot Chat:
"Review this function for security vulnerabilities"
"Is this SQL query safe from injection?"
"What authentication should I add to this endpoint?"
Copilot Privacy Considerations
| Data Type | Copilot Individual | Copilot Business |
|---|---|---|
| Code context sent | Yes | Yes |
| Used for training | Opt-out available | Never |
| Code snippets retained | Depends on settings | Not retained |
| Telemetry | Standard GitHub | Configurable |
Does Copilot store my code?
Copilot sends context to GitHub's servers to generate suggestions. For individual users, data handling depends on your settings. For Business users, code snippets are not retained after generating suggestions. Check GitHub's current privacy documentation for specifics.
Is Copilot-generated code secure?
Not automatically. Copilot generates functional code but doesn't guarantee security. It might suggest insecure patterns, missing validation, or placeholder values. Always review suggestions for security issues before using them.
Can Copilot expose my secrets?
Copilot doesn't intentionally expose secrets, but it might suggest placeholder values that look like real secrets. Use .copilotignore to exclude sensitive files from context, and always use environment variables for real secrets.
Should I use Copilot for security-critical code?
Use it as a starting point, not the final word. For security-critical code, always review suggestions carefully, add missing security checks, and consider having another developer review the code.