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OpenAdvisories
Malicious MAL-2025-191915

ultrafasttelethon

PyPI package · versions 1.39.0, 1.39.0.1, 1.39.0.2, 1.39.0.3

Reported Apr 4, 2025 · Updated Dec 12, 2025

If this package is installed

Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.

Details

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

Indicators of compromise

Shown defanged and not clickable. Search any indicator to find other packages using it.

Domains