# Malicious Package Techniques

## The `setup.py` Install Script

Always check for a setup.py file in a package. 

When you `pip install` a package, during the install process, Python will automatically execute the setup.py file if one exists. This is why you should never run `pip` with sudo or administrator rights. The `setup.py` is an easy target for attackers, so always review the file contents. This attack vector is becoming more known, so you will most likely only catch script kiddies using it.

## The `__init__.py` File

Every package contains an `__init__.py` file, because it is used to mark directories on disk as a Python package. When you import a package, the  `__init__.py` file is automatically executed. This is how the malicious package `ascii2text` was able to run code to steal passwords and upload them to a web hook.

## Package Name Typo Squatting

Adversaries will create package names that mimic popular packages or remove a letter so that you accidentally download their package. 

For example, the malicious package `chekov` typo squatting on the legitimate package `checkov` .

<figure><img src="/files/A6Uo2icY8EBeNBhtkcK9" alt=""><figcaption><p>checkov vs. chekov</p></figcaption></figure>

Not only are the package names similar, but the project description is the exact same.&#x20;

## Package Name Squatting

Package name squatting occurs when a popular python package exists on another site (like Github) and not on pypi.org. Adversaries see this as an opportunity to claim the name on pypi.org and upload a malicious package.&#x20;

This happened to PyTorch back in [December of 2022](https://adamcysec.github.io/PyTorch-dependency-confusion/). PyTorch’s preview build had a dependency called `torchtriton` that was hosted only on their [3rd party package indexer site](https://download.pytorch.org/whl/), therefore an attacker was able to claim this name on pypi.org.&#x20;


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