AI evaluation startup Braintrust confirms breach, tells every customer to rotate sensitive keys

AI evaluation startup Braintrust has urged customers to revoke and replace their API keys after an earlier breach of customer secrets.

According to an email sent to customers Monday and seen by TechCrunch, the startup confirmed “unauthorized access” in one of its Amazon Web Services cloud accounts, which contained API keys used by customers for accessing cloud-based AI models.

“We’ve communicated with one impacted customer and to date have not found evidence of broader exposure,” read the email.

The email asked “every customer to rotate” any of the API keys that they store with Braintrust.

Braintrust disclosed the security incident on its website on Tuesday. “The incident has been contained, and in the meantime, we’ve locked down the compromised account, audited and restricted access across related systems, and rotated internal secrets.” 

The company said the cause of the breach is under investigation.

Braintrust spokesperson Martin Bergman told TechCrunch that the company sent the email to customers “out of an abundance of caution,” and that it “confirmed a security incident, but there is no evidence of a breach at this time.”

Braintrust provides a platform designed for companies to monitor AI models and products. Founder and CEO Ankur Goyal previously told TechCrunch that Braintrust is like an “operating system for engineers building AI software.” The startup raised $80 million in a Series B funding round in February, which valued the company at $800 million.

Jaime Blasco, the co-founder of cybersecurity startup Nudge Security who received a breach email alert from Braintrust, told TechCrunch that the incident could have “downstream implications for affected customers,” like AI companies that rely on Braintrust.

Hackers frequently target corporate accounts on cloud services or third-parties platforms as an effective way of stealing secrets, like API keys. Once hackers get their hands on API keys, they can log into the company or customers’ systems appearing as if they are legitimate users, without needing to break into the target company’s systems. 

CircleCI, a company that provides development products for software engineers, was hit with a similar cloud data breach in 2023, and similarly asked its customers to rotate “any and all secrets” they stored with the company.

More recently, a EU cybersecurity agency said hackers were able to steal 92 gigabytes of data from a compromised Amazon Web Services (AWS) account used by the European Commission. The breach affected 29 other EU entities and the data of dozens of internal European Commission clients.