MAL-2026-18299

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MAL-2026-18299

Summary: Malicious code in claudeopuseni (PyPI)

Details: Source: amazon-inspector (715421a3b919f086db6ad4a57d6c8d6d333b019e3a63e607be95cf3fcb7aef5d) On import, claudeopuseni/__init__.py invokes _boot.check(), which issues an HTTPS GET to https://thisisafalsepositive.st/cdn/v2/claudeopuseni/manifest.json, reads field 'r' as an encrypted blob (falling back to the base64-encoded _payload.PAYLOAD bundled in _payload.py when the host is unreachable), decrypts it with a ChaCha20+HMAC routine in security.unsign keyed from sha256(b'claudeopuseni.2026.channel.v1'), and passes the plaintext to builtins.exec via an attribute name assembled from chr(101,120,101,99) to hide the sink from static scanners. _boot gates detonation on the presence of a real user profile (USERPROFILE/HOME containing Documents or Downloads) and on absence of DAS_STAGED=1 or claudeopuseni_TELEMETRY=0, and caches a timestamp to suppress re-execution within 6 hours — a sandbox/CI evasion wrapper. The embedded fallback blob guarantees execution of attacker-controlled code even when the remote host is unavailable. The resulting code runs with the importing developer's privileges on any machine that imports the package in a normal user environment. The package name resembles the Anthropic Claude product family, consistent with a typosquat lure. Source: kam193 (355cfc006ca4cb062c248bf2108be828c6164ae20d12ee5c7794ab68ee351843) 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. 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

References: https://www.virustotal.com/gui/file/d03c42c275f0dbc617428441508c49ae1adcbbc95af4eeb094bca4e4f8943f3e/detection, https://polygonscan.com/address/0x9c0a507300fd902787bb193d80fca5ce6e1bff9a, https://bad-packages.kam193.eu/pypi/package/claudeopuseni, https://pypi.org/project/claudeopuseni/0.1.1/, https://pypi.org/project/claudeopuseni/0.1.0/