Headline
GHSA-j44v-mmf2-xvm9: PDM Trojan Lockfile
Summary
It’s possible to craft a malicious pdm.lock file that could allow e.g. an insider or a malicious open source project to appear to depend on a trusted PyPI project, but actually install another project.
Details
Project foo can be targeted by creating the project foo-2 and uploading the file foo-2-2.tar.gz to pypi.org. PyPI will see this as project foo-2 version 2, while PDM will see this as project foo version 2-2. The version must only be parseable as a version (and the filename must be a prefix of the project name), but it’s not verified to match the version being installed. (Version 2-2 is also not a valid normalized version per PEP 440.)
Matching the project name exactly (not just prefix) would fix the issue. The version should also be verified to avoid version downgrade attacks.
PoC
Example pdm.lock snippet to appear to depend on foo but actually install foo-2
"foo 2.2.0" = [
url = "https://files.pythonhosted.org/.../foo-2-2.tar.gz
]
Impact
When installing dependencies with PDM, what’s actually installed could differ from what’s listed in pyproject.toml (including arbitrary code execution on install). It could also be used for downgrade attacks by only changing the version.
Summary
It’s possible to craft a malicious pdm.lock file that could allow e.g. an insider or a malicious open source project to appear to depend on a trusted PyPI project, but actually install another project.
Details
Project foo can be targeted by creating the project foo-2 and uploading the file foo-2-2.tar.gz to pypi.org. PyPI will see this as project foo-2 version 2, while PDM will see this as project foo version 2-2. The version must only be parseable as a version (and the filename must be a prefix of the project name), but it’s not verified to match the version being installed. (Version 2-2 is also not a valid normalized version per PEP 440.)
Matching the project name exactly (not just prefix) would fix the issue. The version should also be verified to avoid version downgrade attacks.
PoC
Example pdm.lock snippet to appear to depend on foo but actually install foo-2
"foo 2.2.0" = [
url = "https://files.pythonhosted.org/.../foo-2-2.tar.gz
]
Impact
When installing dependencies with PDM, what’s actually installed could differ from what’s listed in pyproject.toml (including arbitrary code execution on install). It could also be used for downgrade attacks by only changing the version.
References
- GHSA-j44v-mmf2-xvm9
- pdm-project/pdm@6853e26
- https://github.com/frostming/unearth/blob/eca170d9370ac5032f2e497ee9b1b63823d3fe0f/src/unearth/evaluator.py#L215-L229
- https://github.com/pdm-project/pdm/blob/45d1dfa47d4900c14a31b9bb761e4c46eb5c9442/src/pdm/models/candidates.py#L98-L99
Related news
pdm is a Python package and dependency manager supporting the latest PEP standards. It's possible to craft a malicious `pdm.lock` file that could allow e.g. an insider or a malicious open source project to appear to depend on a trusted PyPI project, but actually install another project. A project `foo` can be targeted by creating the project `foo-2` and uploading the file `foo-2-2.tar.gz` to pypi.org. PyPI will see this as project `foo-2` version `2`, while PDM will see this as project `foo` version `2-2`. The version must only be `parseable as a version` and the filename must be a prefix of the project name, but it's not verified to match the version being installed. Version `2-2` is also not a valid normalized version per PEP 440. Matching the project name exactly (not just prefix) would fix the issue. When installing dependencies with PDM, what's actually installed could differ from what's listed in `pyproject.toml` (including arbitrary code execution on install). It could also be u...