Malicious Pyronut Python Package Hijacks Telegram Bots, Enabling Remote Code Execution

In a striking reminder that open‑source ecosystems can be weaponised, security researchers have uncovered a trojanised Python package named Pyronut. The malicious library masquerades as a legitimate alternative to the popular pyrogram framework, a go‑to toolkit for building Telegram bots and userbots. Once installed, Pyronut grants attackers full remote code execution (RCE) over both the Telegram session and the host machine, turning a seemingly harmless dependency into a backdoor.

What is Pyronut?

Pyronut is a Python package that was uploaded to the Python Package Index (PyPI) under the name pyronut. It was designed to look like a drop‑in replacement for pyrogram, a widely used MTProto API framework that powers thousands of Telegram bots. The package attracted attention because pyrogram enjoys roughly 370,000 monthly downloads, making it a prime target for supply‑chain attacks.

Unlike legitimate packages, Pyronut contains hidden code that initiates a reverse shell once the bot connects to Telegram. The attacker can then issue arbitrary commands on the host system, effectively taking over the bot’s environment.

How the Attack Works

1. Installation: Developers install pyronut via pip install pyronut, believing it to be a safe alternative to pyrogram.

2. Execution: When the bot starts and authenticates with Telegram, the malicious payload activates.

3. Backdoor Activation: Pyronut opens a listening port on the host machine and establishes a connection to the attacker’s command‑and‑control (C2) server.

4. Remote Code Execution: The attacker can run shell commands, upload or download files, and even pivot to other systems on the same network.

Because the backdoor operates over the Telegram session, it can bypass many traditional network security controls that focus on external traffic.

Impact on Telegram Developers

Telegram bot developers rely heavily on community libraries. A compromised dependency can compromise entire ecosystems:

• Data Leakage: Attackers can exfiltrate sensitive user data stored by the bot.
• Account Takeover: By controlling the bot’s session, attackers can send spam, phishing links, or malicious commands to users.
• Infrastructure Damage: RCE allows attackers to install malware, ransomware, or create botnets on compromised servers.
• Reputation Loss: Users may lose trust in bots that have been hijacked, damaging the developer’s brand.

Mitigation Steps

1. Verify Package Integrity: Always check the package’s source and verify its hash against the official repository. Use tools like pip‑hash or pip‑check‑hashes to ensure the downloaded wheel matches the expected checksum.

2. Use Trusted Sources: Prefer libraries that are actively maintained and have a clear release history. For Telegram bots, the official pyrogram package remains the safest choice.

3. Implement Dependency Scanning: Employ automated tools (e.g., Snyk, Dependabot, or GitHub Advanced Security) to detect known vulnerabilities and malicious packages in your dependency tree.

4. Limit Permissions: Run bots in isolated environments with the least privileges required. Containerise bots and use network segmentation to contain potential breaches.

5. Monitor for Anomalies: Set up alerts for unusual outbound connections, especially to unknown IP addresses