ESET warns of PromptLock, the first AI-driven ransomware

ESET warns of PromptLock, the first AI-driven ransomware, discovered by ESET Research and reported on 27 August 2025. According to ESET Research, PromptLock uses the gpt-oss:20b model from OpenAI locally via the Ollama API to generate and run malicious Lua scripts on the fly. The ransomware can scan files, steal data, and encrypt them, with Lua scripts that are multi-platform and executable on Windows, Linux, and macOS, and a Golang-written core with both Windows and Linux variants uploaded to VirusTotal.

It can exfiltrate or encrypt user data, and a data destruction feature is present but not yet implemented. PromptLock cryptography relies on the SPECK 128-bit algorithm, and experts believe the sample is likely a PoC or work-in-progress rather than fully deployed malware. The article notes that while multiple indicators suggest it is not yet in the wild, the cybersecurity community should be aware of its potential risks.