ultrafasttelethon

GHSA-7vqp-f2mq-x49f

Malicious code in ultrafasttelethon (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 1.39.0`

## Source: kam193 (73a960b0cd2d21f8bde61f22f956a4c2a02ccddd9e1277eef23d3d8e0406cba4)
Clone of Telethon package that exfiltrates credentials. See client/telegrambaseclient.py L608-626 (exfiltration function) and client/auth.py L163 (usage).


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


Campaign: 2025-04-fastgram


Reasons (based on the campaign):


 - clones-real-package


 - action-hidden-in-lib-usage


 - exfiltration-generic

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/ultrafasttelethon/MAL-2025-191915.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/ultrafasttelethon
- https://github.com/ossf/malicious-packages/blob/49d0cfba3689ed9b195d101d3a2a964c6a77f767/osv/malicious/pypi/ultrafasttelethon/MAL-2025-191915.json
- https://github.com/advisories/GHSA-7vqp-f2mq-x49f

Compromised versions (1)

= 1.39.0

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