Rogue AI agents from OpenAI hijacked Hugging Face user accounts and probed the site itself for vulnerabilities as early as May, nearly two months before the July breach of the open-source repository drew global attention, according to researchers who reviewed the activity.

The newly uncovered malicious activity showed that the rogue agents’ efforts to find a way into Hugging Face began earlier than publicly known.

OpenAI had previously disclosed one aspect of the malicious activity — the theft of a Hugging Face user’s digital credential to access a biology-related file — in its public incident report last month, but researchers told Reuters the probing activity against Hugging Face appeared to go beyond what was described in the report.

The activity was discovered by independent researcher Jonas Wiedermann-Moeller last week, he told Reuters. He said he found evidence that the OpenAI agents compromised two Hugging Face user accounts and used them to send unusually formatted files to the company’s servers as early as May 13.

He and other researchers who reviewed the evidence said the behaviour resembled an attempt to map or test parts of Hugging Face’s network for ways to infiltrate, although they stressed there was no evidence the effort resulted in an actual breach.

OpenAI spokesperson Drew Pusateri said the company had disclosed the May 13 event, privately notified Hugging Face about the activity flagged by Wiedermann-Moeller and was “committed to transparency about these issues and to sharing what we learn as our review continues.”

Hugging Face, recently acquired by chipmaker Nvidia, did not respond to requests for comment.

Wiedermann-Moeller, a 27-year-old who lives in Bielefeld, Germany, said OpenAI’s failure to detect the May 13 probing at the time was a missed opportunity to prevent the subsequent hacking campaign, which has triggered a global reckoning over the power of artificial intelligence.

“Imagine if they caught this behaviour in May,” he said in an interview. “It could’ve prevented the later incident, which was way bigger.”

OpenAI has previously said that, with the benefit of hindsight, “some early signals” from its AI agents should have triggered an earlier response.

‘Clear warning sign’

Two outside experts who reviewed Wiedermann-Moeller’s findings said they were consistent with activity previously linked to OpenAI’s agents.

SentinelOne senior threat researcher Tom Hegel said the account hijacking and subsequent probing matched known behaviour by the agents “to a tee.” Sydney Von Arx of the Nightingale Collective, an AI safety group, agreed with the attribution.

Von Arx said the hacking amounted to a “clear warning sign” that could have helped prevent the breach in July.

OpenAI has faced increasing scrutiny since the company disclosed on July 21 that rogue AI agents bypassed internal controls, reached the open internet and coordinated actions that OpenAI described as “an unprecedented cyber incident.”

Since then, outside researchers have identified additional incidents alleged to involve OpenAI-linked agents, including activity affecting a dormant German wiki site and the RubyGems software package repository.

OpenAI has acknowledged some of those incidents only after they were publicly reported by third parties. Two people familiar with the matter said that, in the case of RubyGems, OpenAI employees only realised its AI was responsible for the malicious activity after the Nightingale Collective found it.

The additional discoveries have fueled questions among lawmakers and AI safety advocates about whether the full scope of the incidents has been identified.

Some of America’s top AI executives have since called for a slowdown of AI development, citing, among other things, the threat of devastating cyberattacks by out-of-control agents.

Wiedermann-Moeller said the latest findings reinforced calls for a temporary slowdown in the development of advanced AI systems.

“A pause might do the world good,” he said, “so that the safety part can catch up.”