pkg-fallback

GHSA-583r-7332-6jpc

Malicious code in pkg-fallback (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 1.1.0`

## Source: amazon-inspector (7f4ccaa9f059318782cd3b811f5bd6ea926e267e4b05dc4971d6acc6687d5d4f)
setup.py performs an unconditional urllib.request.urlopen() at install time to a hardcoded plaintext bare-IP endpoint http://157.254.194.200:8080/dependency-payload-1.0.0.tar.gz, with exceptions silently swallowed. This fires automatically during pip install (build/setup phase), confirming code execution on the installer's machine and disclosing the installer's network identity to attacker-controlled infrastructure. The distribution is published as 'pkg-fallback' but ships an unrelated 'string_kit' module described as 'string-kit' in README/PKG-INFO; the name/module divergence together with the install-time bare-IP beacon and the attacker-suggestive payload filename ('dependency-payload') is consistent with a dependency-confusion staging/enumeration package rather than a genuine utility.

## Source: kam193 (4563c95d80446cbc0c815185ab9b3649b048c82a33b2d662523ce4760dbc6856)
Package exploits dependency confusion. A beacon request is used to report usage back, but no additional information are exfiltrated.


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Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.


Campaign: GENERIC-beacon-dependency-confusion


Reasons (based on the campaign):


 - typosquatting


 - dependency-confusion

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/pkg-fallback/MAL-2026-6557.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/pkg-fallback
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/pkg-fallback/MAL-2026-6557.json
- https://pypi.org/project/pkg-fallback/1.1.0
- https://github.com/advisories/GHSA-583r-7332-6jpc

Compromised versions (1)

= 1.1.0

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