Executive Summary
In March 2026, the 'telnyx' Python SDK was compromised on PyPI via stolen API tokens, resulting in the release of malicious versions 4.87.1 and 4.87.2. The attack is attributed to the threat actor TeamPCP, who previously targeted the litellm package. The compromise is high-impact due to the library's high download volume and its ability to execute code automatically upon package import.
The attack employs a novel delivery mechanism using WAV audio files to smuggle encrypted binaries, bypassing traditional network inspection. On Windows, the malware establishes persistence in the Startup folder, while on Linux and macOS, it executes a multi-stage script to harvest credentials. Collected data is encrypted using AES-256-CBC and a 4096-bit RSA public key before being exfiltrated to an attacker-controlled C2 server.
This campaign highlights the ongoing risk of supply chain attacks targeting CI/CD credentials and the lack of OIDC/Trusted Publisher configurations. Organizations using telnyx should immediately audit for the presence of the malicious versions and rotate any potentially exposed environment variables or credentials.