Google Threat Intelligence Group and Mandiant published research into LLMJacking early November 2026. Criminals are using stolen cloud credentials or API keys to run AI models on a company’s account, gaining access to large language models (LLMs) and expensive GPU processing capacity while the company foots the bill.
Google found fraudulent charges in individual accounts exceeding $100,000 in a single day, with cumulative charges at some companies reaching $1 million before access was removed. The model resembles cryptojacking but abuses paid model resources and can drive rapid increases in cloud costs within hours.
Across Mandiant’s LLMJacking investigations, the company found that the most common entry route was through exposed or stolen cloud identity tokens. These include service account keys, GitHub personal access tokens and active session tokens. One group harvested corporate API keys from public GitHub repositories. The keys typically leak when code is pushed to a public repository without being checked for sensitive information or when session tokens are stolen by malware on a device, or when credentials from earlier breaches are traded on the dark web. Each route gives the attacker valid credentials, so they are simply logging in, and these compromised credentials gave attackers an initial foothold which they then used to expand their permissions, create additional keys or enable LLM services.
