Google warns of 'LLMjacking': Hackers steal AI keys to rack up $100k cloud bills in minutes
Google's Threat Intelligence Group reports that cybercriminals are increasingly hijacking enterprise AI API keys and cloud credentials to run unauthorized workloads, generating massive billing charges rapidly.
Cybercriminals are stealing AI API keys and cloud credentials to hijack expensive large language model (LLM) services, according to a new report from Google’s Threat Intelligence Group (GTIG). The practice, termed "LLMjacking," involves attackers using stolen access to run AI workloads, create proxy services, and rack up massive bills for victims.
Unlike cryptojacking, where mining is relatively slow, LLMjacking costs can escalate extremely quickly. GTIG noted that one threat actor, identified as UNC6993, generated additional API keys within victim cloud projects after acquiring initial access, "quickly accumulating over $100,000 in billing charges." Another actor subscribed victim accounts to Pay-As-You-Go agreements and launched high-volume inference streams, bypassing rate limits by continuously creating and deleting short-lived service accounts.
The report highlights an emerging division of labor in this cybercrime ecosystem. While some groups focus on establishing initial access through exposed endpoints or stolen identity tokens, others known as "LLM Mixers" manage downstream monetization infrastructure. These operators act as routing gateways, proxying, aggregating, and reselling unauthorized LLM access to underground subscribers.
Google urges organizations to increase visibility into their LLM platforms, prioritize detection of modifications to LLM accounts, and enforce the principle of least privilege to mitigate these risks.