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Security researchers have identified a vulnerability in legacy Python packages distributed via PyPI, stemming from outdated bootstrap scripts that reference the now-defunct domain python-distribute[.]org. These scripts, associated with the zc.buildout tool, automate the download and installation of dependencies, including the obsolete 'Distribute' package, by fetching installation scripts from the aforementioned domain. Since the domain is currently up for sale and managed for ad revenue, an attacker who acquires it could serve malicious code to any environment executing these legacy bootstrap scripts, potentially compromising the software supply chain.
The affected packages include widely used libraries such as tornado, pypiserver, slapos.core, roman, xlutils, and testfixtures, among others. While the vulnerable code is largely unused in modern development, it may still be present in legacy production environments, posing a latent risk. The issue highlights the ongoing dangers of abandoned infrastructure and the importance of auditing dependencies and installation scripts, especially in open-source ecosystems where legacy code may persist unnoticed.
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As part of the disclosure, ReversingLabs released a proof of concept and shared affected package names and script hashes as indicators to help defenders identify exposure. The researchers noted no known exploitation of this specific issue.
ReversingLabs researchers identified and publicly disclosed that legacy Python bootstrap scripts could enable a supply chain attack if an attacker acquired `python-distribute.org` and served malicious code to users who manually ran the scripts.
Over time, multiple Python packages continued shipping old `distribute_setup.py` or `bootstrap.py` code that fetched and executed content from the abandoned domain, including `slapos.core` and development versions of Tornado.
The `python-distribute.org` domain, still hard-coded in legacy Python bootstrap scripts, has reportedly been available for purchase since 2014, creating the possibility of a future domain-takeover supply chain attack.
The legacy `distribute_setup.py` mechanism was rendered obsolete in 2013 after Distribute was merged back into setuptools, but the bootstrap pattern remained embedded in some projects.
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