Chronicle/Attacks & incidents

ESET finds PromptLock, ransomware that writes its scripts with a local LLM, later tied to a research prototype

AttackMalwareSignificance assistant-drafted

ESET Research reported PromptLock, ransomware samples uploaded to VirusTotal that use a locally run open-weight model to generate scripts for file discovery, exfiltration and encryption at runtime, and called it the first known AI-powered ransomware. In a September 3, 2025 update, ESET said the authors of an academic study had contacted it and that their research prototype closely resembles the samples, supporting ESET's view that PromptLock was a proof of concept rather than malware used in attacks.

Why it matters

What ESET called the first known AI-powered ransomware closely resembled an academic prototype, a caution about how early AI-malware claims are read.

Key facts

As stated in the sources, with where to find them.

  • PromptLock runs OpenAI’s gpt-oss-20b model locally through the Ollama API to generate Lua scripts from hard-coded prompts.Article body
  • Windows and Linux variants were found on VirusTotal; ESET did not see PromptLock in actual attacks.Article body
  • Update, September 3, 2025: an academic study, Ransomware 3.0, describes a prototype that closely resembles the samples.Update note

Findings that cite this record

No tracked finding cites this record yet.

Key questions this bears on

Sources