│ Category: Git
│ Author: Imattas aka Zemi
│ Flag: byuctf{I_lov3_s3cr3t_files}
│ Source Path: Gitastic-Containerized/Gitastic-Solutions/Gitastic5
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--[ Challenge Description ]--
-- text --
Description:
We're certain that someone critical info in the secrets.txt file yet we can't
see anything. It's like someone has replaced it with something else! We need you
to get to the bottom of this mysterious case
git clone git://gitastic.csa.cyberjousting.com/challenge
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--[ Provided Materials ]--
- Repository folder https://github.com/BYU-CSA/BYUCTF-2026/tree/main/Gitastic-Co
ntainerized/Gitastic-Solutions/Gitastic5
- Gitastic-Containerized/Gitastic-Solutions/Gitastic5/README.md https://github.c
om/BYU-CSA/BYUCTF-2026/blob/main/Gitastic-Containerized/Gitastic-Solutions/Gitas
tic5/README.md
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--[ Recon / Initial Analysis ]--
This page imports the BYUCTF 2026 source material for the Git challenge Gitastic
5. The prompt is kept separate from the solve notes, and upstream artifacts are
linked so the challenge can be replayed from the original repository.
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--[ Vulnerability / Observation ]--
The useful observation comes from the imported solve notes below. I kept the
original technical path intact while normalizing the page metadata, challenge
grouping, and author attribution for the Volume 2 writeup archive.
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--[ Exploitation / Solution ]--
Source: Gitastic-Containerized/Gitastic-Solutions/Gitastic5/README.md https://gi
thub.com/BYU-CSA/BYUCTF-2026/blob/main/Gitastic-Containerized/Gitastic-Solutions
/Gitastic5/README.md
This is the hardest challenge of the gitastic series.
1) Run git log to find the hash of the first commit is
f88c2adbe25705ad54cabfd0c84826235446ffd0.
2) They will also find in the commit message a message talking about checking if
something has replaced it.
3) Run git fetch origin 'refs/replace/*:refs/replace/*'. If they then run git
log again they'll notice that the log has changed to say 'replaced' on the
commit at the top.
4) If they run git show-ref it'll show them replace refs at the top of the
output. They're able to see the hash of the last commit.
5) From the last command they can see that there's a tie to the hash of their
current git commit. This gives them the hash of
b82f2081365d48f0366d22c07d40b2ae8279de0c.
6)They can run git --no-replace-objects show
b82f2081365d48f0366d22c07d40b2ae8279de0c to see what hidden file is actually
there.
Flag - byuctf{I_lov3_s3cr3t_files}
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--[ Full Exploit Script ]--
No standalone exploit script was present in the selected source material.
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--[ Key Takeaways ]--
- The BYUCTF 2026 challenge material is preserved with local archive formatting.
- The page author is normalized to Imattas aka Zemi.
- The source repository remains linked for handouts, services, and solve
artifacts.