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50 lines
1.4 KiB
50 lines
1.4 KiB
+++
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author = "Maik de Kruif"
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title = "Challenge 0"
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subtitle = "Challenge 0 - AdventOfCTF"
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date = 2020-12-02T17:20:28+01:00
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description = "A writeup for challenge 0 of AdventOfCTF."
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cover = "img/writeups/adventofctf/2020/f90b2bf3f08ee628c09505ff309018ed.png"
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tags = [
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"AdventOfCTF",
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"challenge",
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"ctf",
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"hacking",
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"writeup",
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"web",
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]
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categories = [
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"ctf",
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"writeups",
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"hacking",
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]
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+++
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- Points: 1
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## Description
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Do you remember the flag in the teaser website?
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## Solution
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Sadly, the teaser website isn't online anymore. If only someone kept an archive of the internet. This is where the Wayback Machine on [archive.org](https://archive.org/) comes in handy.
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So, let's use the Wayback Machine to get the teaser page. <https://web.archive.org/web/20201112020839/https://adventofctf.com/>
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When we take a look at the source html of the page we find the following comment:
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```html
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<!-- Ceasar worked on this you know. Tk9WSXtIRVlfMVNfVGgxU19AX0ZsYTk/fQ== -->
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```
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It looks like some encoded string. If you've been doing CTFs for a while you'll probably recognize it's encoded in `base64`. We can use the program `base64` to decode this string.
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```bash
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> echo "Tk9WSXtIRVlfMVNfVGgxU19AX0ZsYTk/fQ==" | base64 -d
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NOVI{HEY_1S_Th1S_@_Fla9?}
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```
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We found the flag! It's `NOVI{HEY_1S_Th1S_@_Fla9?}`.
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This flag can then be submitted for the [challenge](https://ctfd.adventofctf.com/challenges#0-1).
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