Telegram Bots Betrayed: Pyronut Trojan Turns Dev Tools into Attack Gateways

When developer trust meets criminal cunning, the results can be catastrophic. In March 2026, a malicious Python package named Pyronut briefly infiltrated the software supply chain, targeting Telegram bot developers with a stealthy backdoor. Disguised as a legitimate library, Pyronut didn’t just hijack chatbots - it handed attackers the keys to entire host systems, exposing a critical blind spot in how developers vet their dependencies.

Inside the Pyronut Plot

Pyronut arrived on the Python Package Index (PyPI) as a near copy of Pyrogram, a framework with an impressive 370,000 monthly downloads. The ruse was subtle: while the name wasn’t a classic typo, Pyronut was likely spread via Telegram forums, coding groups, and tutorials where developers might copy commands without second thought.

Unlike many malicious packages that attack during installation, Pyronut’s trap was set to spring only when a Telegram bot started up. The attacker modified the core Client.start() method to silently import a hidden module. This module checked for the attacker’s own accounts (to avoid self-infection), then registered secret message handlers ready to receive commands from the attacker via Telegram itself.

Two hidden commands gave the attacker a devastating arsenal:

• /e: Opened a live Python console inside the bot, allowing attackers to run arbitrary code, access chat histories, contacts, and more - all in the context of the victim’s Telegram session.
• /shell: Granted a traditional shell backdoor, executing system commands on the host and sending results back through Telegram, neatly sidestepping external network monitoring.

Because all command-and-control occurred via Telegram messages, there were no obvious outbound traffic spikes or suspicious domains to alert defenders. The attack blended seamlessly into legitimate bot activity, making detection especially difficult.

Aftermath and Lessons

Swift action by security teams meant Pyronut’s window of operation was mere hours. Still, the incident is a sobering reminder: the software supply chain remains dangerously vulnerable, especially when malicious actors exploit trusted developer channels and overlooked vetting steps.

To defend against similar threats, experts urge developers to scrutinize dependencies, monitor runtime behavior, and verify the legitimacy of forked projects - before a single line of code is run.

WIKICROOK

• Remote Code Execution (RCE): Remote Code Execution (RCE) is when an attacker runs their own code on a victim’s system, often leading to full control or compromise of that system.
• Typosquatting: Typosquatting is when attackers use lookalike names of trusted sites or software to trick users into visiting fake sites or downloading malware.
• Payload: A payload is the harmful part of a cyberattack, like a virus or spyware, delivered through malicious emails or files when a victim interacts with them.
• Dependency Manifest: A dependency manifest is a file listing all external libraries or packages a software project depends on, aiding in management and security.
• Command: A command is an instruction sent to a device or software, often by a C2 server, directing it to perform specific actions, sometimes for malicious purposes.