OpenAI has published an open letter on global cyber defense, co-signed by more than 100 companies, according to The Decoder. The reported signatories include Microsoft, Google, AWS, Anthropic, Cisco, CrowdStrike, Deutsche Telekom, SAP, and Mastercard. The letter warns that AI-enabled cyberattacks will become more common and more sophisticated, The Decoder reports. It identifies critical infrastructure, including hospitals and water utilities, as among the areas at highest risk. The coalition’s argument is not only that AI will improve attackers’ capabilities. According to The Decoder, the signatories also say recent AI advances are giving defenders new ways to address long-running security weaknesses, including unpatched software and weak authentication. The letter calls for several groups to move at once. Companies are urged to make cybersecurity a C-suite priority; governments are urged to increase funding and coordination; and AI companies are urged to make security tools affordable for underfunded organizations, The Decoder reports. The Decoder also points to a joint warning from the National Security Agency, the Cybersecurity and Infrastructure Security Agency, and the Federal Bureau of Investigation in mid-August. According to The Decoder’s summary, that warning said attackers are already using AI to write exploit scripts targeting industrial control systems such as Siemens S7 across U.S. energy, water, chemicals, and manufacturing sectors. Because this cluster includes only one source, the story should be treated as developing rather than fully confirmed from the provided material. The newsworthy point is clear: major AI, cloud, telecom, security, and enterprise software companies are publicly aligning around the view that AI-powered cyber risk to critical infrastructure requires immediate defensive investment. Who benefits: Security vendors and AI providers offering defensive tools could benefit if companies and governments act on the letter’s recommendations. Underfunded organizations would benefit if affordable tools actually become available, as the signatories urge. Who's exposed: The exposed groups named in the reporting are hospitals, water utilities, and other critical infrastructure operators. The Decoder also cites U.S. energy, water, chemicals, and manufacturing sectors in connection with the government warning.