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49 lines
1.4 KiB
49 lines
1.4 KiB
+++
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author = "Maik de Kruif"
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title = "Challenge 1 - AdventOfCTF"
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date = 2020-12-02T17:27:25+01:00
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description = "A writeup for challenge 1 of AdventOfCTF."
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cover = "img/adventofctf/3f12301d8715a1371d2d776d25ea6ab6.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: 100
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## Description
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All starts should be easy
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Visit <https://01.adventofctf.com> to start the challenge.
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## Solution
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When opening the page, we're asked for Santa's password. Unfortunately, we don't know the password. Don't stop there though, mayby someone has hidden it in the source html.
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Let's open the source by pressing `Ctrl + U` and take a look at it. Near the bottom we find the following comment:
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```html
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<!-- This is an odd encoded thing right? YWR2ZW50X29mX2N0Zl9pc19oZXJl -->
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```
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This looks like a `base64` encoded string so let's use the program `base64` with the `-d` decode flag to decode the text.
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```bash
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> echo "YWR2ZW50X29mX2N0Zl9pc19oZXJl" | base64 -d
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advent_of_ctf_is_here
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```
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We get some plain text. If we enter it as Santa's password on the challenge page, it gives us the flag: `NOVI{L3T_7H3_M0NTH_0F_FUN_START}`.
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This flag can then be submitted for the [challenge](https://ctfd.adventofctf.com/challenges#1-2).
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