Encoding Is Not Encryption

Base64 Misuse • Beginner

Data Encoding

Secure Mode• show fix Session• Cookie Recruiter• Mode

Objective: Recover a sensitive value hidden with encoding.

Try: Decode the exposed value.

🧩 Design: Transform the data. If it’s reversible, it’s not protection.

Everything here is simulated and sandboxed to this site—no real accounts, no real services.

Demo How it works Issue Exploit Fix Video

1) Demo

Here is the feature “working” as implemented in this mode.

App Output

Exposed Value

U0VDUkVUX0FQSV9LRVlfREVNTw==

Hint: Base64 is reversible.

Decoded Output

(click decode by adding ?decode=true)

Response

Status: 200 OK Response Headers: (none)

2) How the code works

This section shows the mental model: what the server is “thinking”.

return { secret: base64(secret) };

3) The issue

Base64 is reversible. It hides nothing.

Real-world impact: Real apps leak API keys when they ‘obfuscate’ them client-side.

4) Exploit it

Edit the raw request below. You can change method, path/query, headers, and body. Then send it. The server will parse what you typed and re-run the simulation.

Request Editor

Tip: For secure mode tests, add a cookie like: Cookie: session=1; role=Admin

Parsed View (what the server read)

method: GET path: /config headers: host: kylerburke.dev body: (empty)

Exploit Editor Hidden (Recruiter Mode)

This mode is designed for sharing your portfolio. It focuses on clear explanation, real-world impact, and fixes—without interactive exploitation.

Want to demo the exploit? Turn Recruiter Mode off and use the Request Editor.

5) Fix

Secure Mode shows the fix behavior. Flip modes and send the same request.

Keep secrets server-side; never ship them to the browser.

Video

Short visual explanation to match what you just did.

Swap the YouTube ID in the Worker to pick a different explainer video for this vulnerability.