flashsimplelogger

GHSA-wcfp-wvw2-2cx6

Malicious code in flashsimplelogger (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 0.1.0`

## Source: kam193 (8c4753ee44e481f1f689cfaeddcddaef8dcdf86fbb1db19b3fe0acc2fadac305)
It's a clone of "loguru" package which on import loads a second-stage script from loguru[.]guru. This makes a few checks and downloads the next stage, which is a code obfuscated with PyArmor with unclear behaviour.

The way the malicious code has been embedded could be called a "sophisticated" threat. The code is in the _logger.py in two places: the payload in L2242 as a long string constraint of only whitespaces, which are then transformed into bits and bytes, and later compiled and executed using "types.FunctionType" during initialisation of Core class.


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


Campaign: 2025-07-loquru


Reasons (based on the campaign):


 - typosquatting


 - obfuscation


 - clones-real-package


 - Downloads and executes a remote malicious script.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/flashsimplelogger/MAL-2025-191729.json))

**References:**
- https://github.com/Delgan/loguru/issues/1363
- https://bad-packages.kam193.eu/pypi/package/flashsimplelogger
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/flashsimplelogger/MAL-2025-191729.json
- https://github.com/advisories/GHSA-wcfp-wvw2-2cx6

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.