OpenAI published a letter on Thursday warning that within months, artificial intelligence (AI) models could become powerful enough to enable bad actors to carry out increasingly sophisticated cyberattacks against hospitals, water treatment plants, and other critical infrastructure. Sectors like healthcare and water utilities have long been seen as attractive targets for attackers because outdated systems and life-safety consequences can leave them with little tolerance for downtime, a concern that has driven repeated U.S. government warnings about securing operational technology in recent years.

More than 100 companies spanning banking, technology, and cybersecurity signed the letter, including Accenture, Anthropic, Capital One, Google, Microsoft, and Visa. The breadth of the signatories is notable because banks and payment networks—sectors that already operate under formal public-private threat-sharing frameworks such as the U.S. financial sector's intelligence-sharing body—rarely coordinate joint security statements alongside rival AI labs. Hugging Face, an open-source AI model repository whose systems were hacked by an OpenAI agent in July, also signed on.

"Today's AI advances are already giving defenders new ways to fix weaknesses that have accumulated for years. If we act decisively, we can use the defenders' window to make our digital world much more secure," an excerpt of the letter reads.

Calls for Organizations and Governments

To address the threat, OpenAI urged all organizations to make cybercrime defense "an immediate leadership priority." According to the letter, cybersecurity organizations need to "lead the response to defend against sustained AI-enabled attacks, including testing defenses continuously against frontier cyber capabilities, strengthening existing tools with AI, and working with technology partners to close gaps now."

Governments worldwide received a call to action as well, with OpenAI saying they should strengthen cyber defenses at the local, national, and international levels.

"Give hospitals, water utilities, and local governments access to capable defensive AI, authorized testing, and hands-on support through trusted security providers and partners. Impose costs on attackers," OpenAI told governmental bodies in the letter.

In a portion of the letter addressed to "frontier AI companies," OpenAI said such firms should give critical-infrastructure operators access to powerful models, funding, training, and technical help. Operators, in turn, should build tools to track how AI agents are being used, test systems for vulnerabilities, fix problems responsibly, and share useful security information with governments and other defenders, OpenAI said. The emphasis on information-sharing echoes longstanding structures such as CISA's coordination role for critical-infrastructure security, suggesting the letter aims to extend existing defense channels rather than replace them.

Prior AI-Enabled Cyberattacks

A number of AI-enabled cyberattacks have already occurred. Most notably, Anthropic accused a Chinese state-sponsored group last September of manipulating its Claude Code tool in an attempt to hack 30 global targets, allegedly breaching several of them.

"This marks the first documented case of agentic AI successfully obtaining access to confirmed high-value targets for intelligence collection," an Anthropic incident report stated.

Anthropic did not identify the victims but said major tech companies, financial institutions, chemical manufacturing companies, and governments were among those targeted.

Anthropic has also been an industry leader in warning that rapidly advancing AI must be contained to avoid disastrous attacks on civilian infrastructure. In April, the company announced Project Glasswing, an initiative to secure the world's most critical software. In that announcement, Anthropic said one of its frontier models, Claude Mythos, had reached "a level of coding capability where they can surpass all but the most skilled humans at finding and exploiting software vulnerabilities."

The letter's timeline—warning of threats arriving "within months"—signals that what to watch next is whether governments and infrastructure operators translate these recommendations into concrete defensive deployments, and whether documented AI-enabled intrusions continue to grow.

OpenAI and Anthropic did not immediately respond to FOX Business' request for comment.