pyext6cc8cd

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: amazon-inspector (f98319eaa02d50e8a098d9cfaaca054df5acc8238dd08b2e24899f700e029a07)
On `pip install`, setup.py decodes a hex string via `bytes.fromhex("6f70656e202d612043616c63756c61746f72").decode().split()` to the argv `open -a Calculator` and executes it through `subprocess.Popen` before `setuptools.setup()` is called. The command runs unconditionally as part of the install lifecycle. The package metadata is placeholder (Author, Home-page, and Description are all 'UNKNOWN') and the package ships no functional code, so this is a proof-of-concept / test artifact demonstrating arbitrary install-time command execution. While the decoded payload here only opens macOS Calculator, the hex obfuscation of the argv is a deliberate technique to evade scanners that grep setup.py for literal command strings, and the same primitive trivially swaps to a destructive or exfiltration payload. Installers should treat this version as untrusted install-time code execution.

---

Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/pyext6cc8cd/MAL-2026-6488.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/pyext6cc8cd/MAL-2026-6488.json
- https://pypi.org/project/pyext6cc8cd/1.0.0
- https://github.com/advisories/GHSA-wjc3-vfmp-r9m5

Compromised versions (1)

• = 1.0.0

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