2026-08-21 13:51:31 +07:00
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---
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title: "Sweet Cookie — Base64 Cookie"
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2026-08-21 14:28:04 +07:00
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type: "writeup"
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section: "writeups"
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status: "published"
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author: "asep"
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tags: ["gemastik", "ctf", "warmup", "web"]
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path: "writeups/gemastik-2026-warmup/ch6-sweet-cookie.md"
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created_at: "2026-08-21T07:25:31.627Z"
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updated_at: "2026-08-21T07:25:31.627Z"
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2026-08-21 13:51:31 +07:00
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event: "GEMASTIK 2026 Warmup"
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2026-08-21 14:28:04 +07:00
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challenge: "Sweet Cookie — Base64 Cookie"
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2026-08-21 13:51:31 +07:00
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category: "web"
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points: 500
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difficulty: "easy"
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flag: "GEMASTIK19{c00k13_b4s3_d3c0d3}"
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---
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# Sweet Cookie (500 pts) — Web
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**URL:** `http://15.232.89.109:8002/`
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Server mengirim cookie `session`. Nilainya cuma di-encode **Base64** (JSON):
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```python
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import base64
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# Cookie value from Set-Cookie header
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cookie = "eyJ1c2V..." # nilai session cookie
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decoded = base64.b64decode(cookie)
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print(decoded)
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# {"user": "guest", "flag": "GEMASTIK19{c00k13_b4s3_d3c0d3}"}
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```
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## Flag
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2026-08-21 14:28:04 +07:00
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`GEMASTIK19{c00k13_b4s3_d3c0d3}`
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