ctf-toolkit

GHSA-3749-xv6x-4pwg

Malicious code in ctf-toolkit (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 0.1.0`

## Source: kam193 (e47981485066b674150cc4d9d3709e41707e69111f188e54e772becc7349ab89)
The package states to contain a modified curl library to allow low-level request modifications. However, there is also undisclosed malicious behavior:

1. The package installs a .pth file directly in the site-packages directory, effectively running a special code on each Python usage.
2. This code performs "TLS context warm-up" by contacting a URL (Github) in the background, in a separate process; this is suspicious on its own as it's unclear how a separate process can warm up further requests in the main process, but...
3. ...besides the URL given in the code above, the library always contacts a hardcoded URL, identifying itself as a VPN client.

Additionally, there is no source code of the modified library anywhere, and the related Github hosting the package code account is 1-day old.


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Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.


Campaign: 2026-02-ctf-toolkit


Reasons (based on the campaign):


 - The package contains code to exfiltrate basic data from the system, like IP or username. It has a limited risk.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/ctf-toolkit/MAL-2026-1085.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/ctf-toolkit
- https://github.com/Wang-SecurityResearch/ctf_toolkit
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/ctf-toolkit/MAL-2026-1085.json
- https://web.archive.org/web/20260228111147/https://github.com/Wang-SecurityResearch
- https://github.com/advisories/GHSA-3749-xv6x-4pwg

Compromised versions (1)

= 0.1.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.