Victim organizations are losing millions of dollars in token charges as criminals hijack their corporate LLM access to steal expensive computing resources and AI services. These fraudulent charges from resource consumption can exceed $100,000 a day, according to a Monday report by Google's Mandiant incident responders, who saw cumulative charges at some organizations hit $1 million before the victim companies revoked intruders' access. "Whenever possible, threat actors want to use this technology to gain a scale advantage over defenders. They achieve that with agentic tools and by stealing tokens from unwitting third parties,” John Hultquist, chief analyst at Google Threat Intelligence Group, told The Register. “Locking down these resources will not only protect organizations from runaway costs, but also protect the broader community from a deluge of cheap, autonomous attacks.” This tactic of hijacking access to LLMs is called LLMJacking, and it’s been increasing steadily over the past two years. In one extreme case, documented in an August report from CrowdStrike, a token thief sent about 200,000 API requests in just two minutes. In one case detailed in the report, a group Google tracks as UNC6993 illicitly gained access to LLM API keys, then generated additional keys and enabled services within the victim’s cloud projects, racking up $100,000 in charges. The threat intel biz also documented a different token thief subscribing victim accounts to Pay-As-You-Go agreements to access advanced models on the victim company’s dime. The crook selected premium foundation models, launched high-volume inference streams, and used a “burn and rotate strategy” to bypass rate limits by creating and deleting short-lived service accounts while auditing the billing interface to monitor financial impact. In yet another incident, an intruder executed more than 500,000 LLM API calls in less than eight hours using stolen third-party API keys to power a token routing service called Jet Night, according to a Monday report from Google. “Given Jet Night’s per-token costs to users are so far below typical market rates GTIG believes the service relies on stolen keys to operate profitably,” the report says. “For example, Jet Night offers an unlimited token plan for approximately $60 USD per month with alleged access to frontier models, a consumer service level that would typically run between $100 and $250 per month.” Jet Night has also admitted to multiple outages on its public Telegram channel, which the Google threat hunters note is “likely due to stolen keys being revoked as victims discover their respective compromises.” Specialized LLMjacking roles As more criminals join the LLMJacking ecosystem, Google says it has documented a division of labor between the criminals that establish initial access to compromised cloud and AI services, and those that manage downstream monetization infrastructure, called “LLM Mixers.” In one case that Mandiant responded to in mid-2026, UNC6993 compromised a cloud instance through a misconfigured Service Account key and used this access to grant further access to a model API. The crooks also spun up a session hijacking page purporting to be an application portal to join a group of LLM users. “This page tricks users into navigating to the legitimate LLM service website, and pasting their raw JSON payload containing an active access token, which was then posted to the backend API to bypass password and multifactor authentication (MFA) controls,” the report says. Google predicts miscreants will “increasingly prioritize LLMJacking” compared to other types of resource theft like cryptojacking. And to prevent cloud LLM service abuse, the security firm says defenders should prioritize identity and access management plus supply chain security, and use a centralized secrets management platform to rotate keys and secrets. Also apply least-access privileges to users and service accounts, ensuring that they only have permissions necessary to complete their roles and tasks. And automate secrets scanning within codebases to identify and then remove any API keys and secrets added to source code. ®
:format(jpeg):fill(f8f8f8,true)/s3/static.nrc.nl/taxonomy/cd714fc-Vos%2520Marjoleine%2520de%25202023%2520%255BDoomernik%25202319%255D%25201280.png)
