Trump's Anthropic crackdown rattles cyber defenders

• Cybersecurity experts are worried about the long tail this ongoing feud will have on American cyber defenses.
• "They've set a precedent that American models can't do defensive security research," former Facebook security chief Alex Stamos tells Axios.

Driving the news: Stamos organized an open letter, signed by nearly 150 security leaders, calling on the Trump administration to reverse its move to restrict access to Anthropic's Fable 5 and Mythos 5.

• Concerns about Chinese access to Mythos and a call from Amazon CEO Andy Jassy reportedly sent the administration into a panic last week after Anthropic publicly released its first Mythos-class model.
• During the spat, Anthropic brought in a leading zero-day bug hunter — who helped the Defense Department create its bug bounty program and sat on multiple government-led advisory boards — to help assess Amazon's concerns about the security of Fable and Mythos.
• Now, the administration is casting the security researcher as a "radical Democrat," as my colleagues reported yesterday.

Between the lines: The dispute has quickly shifted from a fight over one model to a broader question of whether the government is creating unwritten rules for AI security research.

• Stamos, who has spoken with the technical staffs involved in the fallout, said the findings Amazon flagged do not appear unique to Anthropic's models.
• Multiple people familiar with Amazon's concerns said they centered on a jailbreak the company found that allows Fable to write "proofs of concept" — a capability security teams often use to understand and fix vulnerabilities.
• Katie Moussouris, CEO of Luta Security, said in a detailed blog post yesterday that she saw a copy of Amazon's findings and the issue didn't involve mass exploitation of the model, but rather prompts designed to support defensive security work.

Flashback: Before releasing Fable 5, Anthropic said, it worked with both internal teams and outside security researchers to test the model for jailbreaks and other flaws.

• The company has also argued that "perfect jailbreak resistance is not currently possible for any model provider," so it has focused on making "jailbreaks either narrow ... or very expensive to produce."

Threat level: Cyber experts warn that if frontier AI companies fear punishment for models that can identify vulnerabilities, they may now be tempted to strip out capabilities on which defenders already rely.

• Moussouris noted in an X post that there is no fix that wouldn't render the model less useful for cyber defenders.
• "No new frontier models can be developed or released if this is the administration's best take," she added.

The big picture: Researchers argue the administration's response risks giving adversaries an advantage.

• Researchers note that Chinese AI developers and government-backed hacking groups are unlikely to abandon similar tools, raising concerns that U.S. defenders could lose access to abilities their adversaries are using.
• "This is closer to China than what I recognize as the United States, and personally I see this as a huge threat to American dynamism," Stamos said.

What to watch: The U.S. government is in the process of standing up a vulnerability clearinghouse via the recent AI security executive order that would likely triage reports about jailbreaks, prompt injections and other threats to AI models.

• But questions linger about how much cybersecurity talent remains in the Trump administration after several White House departures in recent weeks and the sidelining of the nation's top cyber agency.

Go deeper: The hidden risk of Trump's Anthropic crackdown