First AI-Powered Ransomware “PromptLock” Uses OpenAI gpt-oss-20b for Encryption

PromptLock is described as the first AI-powered ransomware that uses a local large language model to generate its payload, discovered by the ESET Research team. It does not ship with pre-compiled attack logic; instead, it contains hard-coded prompts that instruct a locally hosted OpenAI gpt-oss:20b model—accessed via the Ollama API—to craft Lua scripts for each stage of the attack.

According to ESET Research, PromptLock samples were found in both Windows and Linux variants on VirusTotal, and the malware is written in Golang, issuing POST requests to a local Ollama API endpoint to generate the Lua code on the fly. The tool’s Lua-generated modules perform system enumeration, file system inspection, data exfiltration, and encryption, with encryption handled by the SPECK 128-bit block cipher for cross‑platform use.

While described as a proof-of-concept rather than a widespread campaign, the analysis highlights a shift towards on-endpoint, AI-driven payload assembly and emphasises hardening of local inference APIs and monitoring anomalous script generation behavior. according to ESET Research