Cloud hosting provider Railway has disclosed that hackers stole customer secrets from its systems in October and ran up about $740,000 in unauthorised charges on stolen artificial intelligence service keys. In an incident report published on 10 November, the company said the attackers used AI-powered agents to find and exploit weaknesses across its infrastructure in a roughly 26-hour battle with its engineers.

How the attackers got in

The attack began at 07:28 UTC on 20 October, when the intruders exploited a previously unknown flaw in Railway's multi-tenant build system to partly escape filesystem isolation and take a build credential. Early on 21 October they used a misconfigured identity trust setting to obtain short-lived cloud credentials, reach a machine holding a long-lived decryption key, and decrypt customer environment variables. They were evicted at 09:24 UTC that day.

Scale of the exposure

Railway said at most 1.85% of its workspaces, about 100,000, could have had environment variables decrypted, although that is an upper limit rather than a confirmed count. Linked-account tokens belonging to 1,852 users were exposed and have been reset. The company found no evidence that customer databases were accessed or that stolen credentials were used to log into accounts. It is working with AI providers on refunds and says it will cover charges that providers decline to reimburse. Railway believes the keys were taken for resale or for training rival AI models, and links the intrusion to a wider campaign against AI developer platforms that security firm Wiz calls “Black October”.