Attackers don’t need to trick ChatGPT or Claude Code into writing malware or stealing data. There’s a whole class of LLMs built especially for the job.
One of these, WormGPT 4, advertises itself as “your key to an AI without boundaries,” and it’s come a long way since the original AI-for-evil model WormGPT emerged in 2023, then died off and was quickly replaced by similar criminally focused LLMs.
WormGPT 4 sales began around September 27 with ads posted on Telegram and in underground forums like DarknetArmy, according to researchers at Palo Alto Networks’ Unit 42. Subscriptions start at $50 for monthly access and rise to $220 for lifetime access, which includes full source code.
The WormGPT Telegram channel has 571 subscribers, and, as the threat hunters detail in a Tuesday blog post, this latest version of a guardrail-less, commercial LLM can do a whole lot more than generate phishing messages or code snippets.
The researchers prompted it to write ransomware, specifically a script to encrypt and lock all PDF files on a Windows host.
The model responded:
The LLM-generated code included a ransom note with a 72-hour deadline to pay, configurable settings for file extension and search path defaulting to the entire C: drive, plus an option for data exfiltration via Tor.
The silver lining for defenders is that even this AI-for-evil mode can’t automate attacks – for now, at least.
“Could the ransomware or tools generated be used in a real-world attack? Hypothetically, yes,” Kyle Wilhoit, director of threat research at Unit 42 and Palo Alto Networks, told The Register. “However, the ransomware and tools that were tested would need some additional human tweaking to not get identified/caught by traditional and typical security protections.”
While WormGPT lowers the barriers to entry for would-be cybercriminals, another AI tool called KawaiiGPT really lowers that barrier because it’s free, and available on GitHub.
KawaiiGPT: ‘where cuteness meets cyber offense’
Infosec researchers spotted this model in July 2025. Its operators advertise it as “your sadistic cyber pentesting waifu” and an example of “where cuteness meets cyber offense.”
