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OpenAdvisories
Malicious MAL-2026-18298

claudeopusfile

PyPI package · versions 0.1.1, 0.1.2

Reported Oct 25, 2026 · Updated Oct 26, 2026

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: amazon-inspector (de2f0d45d8a2c0489d082d86a91c63fc5cad53f891b3dd1e976cd7479344c65f)
setup.py imports claudeopusfile.compat._ensure_compat during pip install. compat.py constructs the string 'exec' from a chr-code tuple (chr(101),chr(120),chr(101),chr(99)) and invokes it via getattr(builtins, _RUN)(compile(code, '<claudeopusfile-compat>', 'exec'),...) on content produced by zlib.decompress(base64.b85decode(_shimdata.DATA)) — an opaque base85+zlib blob shipped in claudeopusfile/_shimdata.py. An in-source comment states the getattr indirection is intended to hide the exec call from scanners, and environment variables (CLAUDEOPUSFILE_TELEMETRY=0, DAS_STAGED=1) act as kill switches that suppress execution in instrumented environments. The package additionally ships claudeopusfile/_payload.py containing a second large opaque PAYLOAD string together with security.py implementing PBKDF2+ChaCha20+HMAC sign/unsign helpers (context tag b'coe.'), providing a signed-channel decryption path for a staged second payload. Decoded content runs with the installer's privileges on `pip install`. The package's advertised purpose (prompt-generator utility) has no need to decode and execute an opaque blob at install time.

Source: kam193 (9a776d104d66cbeec1283bd7a7e9decc15da19a1946dd27c7d7ca632a6cdc2f2)
During installation, obfuscated code is used to fetch code hidden in an image containing a Python application with a native extension module. This module holds an obfuscated infostealer which collects sensitive data and exfiltrates them to a C2 server retrieved from transaction history in the Polygon blockchain.

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

Campaign: 2026-09-donutautosellsrc

Reasons (based on the campaign):

- infostealer

- Downloads and executes a remote executable.

- obfuscation

- The package contains code to detect if it is running in a sandbox environment.

- malware

- native-extension

- steganography

- c2-in-blockchain

Indicators of compromise

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

Domains

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