Japan’s nationwide J-Alert emergency warning system lacks encryption and a mechanism to authenticate the source of data transmitted via satellite, creating the potential for specially crafted fake data to trigger false emergency alerts, according to a Kyodo News report.
Yudai Kirishiki of Tokyo-based cybersecurity firm Unknown Technologies identified the issue after analyzing a J-Alert receiver previously used by a local government that was sold on the secondhand market. Testing found that the receiver could not distinguish fake information formatted like legitimate J-Alert data, demonstrating that a third party could potentially transmit a false warning.
J-Alert distributes urgent information about earthquakes, tsunamis, ballistic missile launches and other emergencies from government agencies via satellite to receivers operated by municipalities and other public organizations.
A source at Japan’s Ministry of Internal Affairs and Communications acknowledged the security issue, while an official said the government continues to work to ensure stable operation of the system.
ㅤLarry Pesce, VP of Services, Finite State:
“Two things in this J-Alert story jump out. First, the claim that satellite attacks “weren’t considered a real threat” in 2007. Brazilian pirates had been hijacking US Navy satellite transponders for decades by then, and Captain Midnight took over HBO’s satellite feed in 1986. Unauthenticated satellite traffic being spoofable was not a new idea.
“Second, and more important: the researcher got a decommissioned receiver off the secondhand market. Disposal instructions went out after the fact. Once an adversary has the hardware, “we can’t share details for security reasons” stops being a control. They can pull the firmware, reverse the protocol, and test spoofed alerts against the real parser until it works. This is supply chain and lifecycle risk in its plainest form: sensitive hardware will leave your control, so design as if it already has.
“The fix here isn’t exotic. Public alerts don’t need to be secret, they need to be signed. Receivers that verify the source would make a drone and a stolen receiver far less useful. For a system that can move an entire population, that should have been in the original design.
“Once a decommissioned receiver shows up for sale, the government’s decision not to share details ‘from a security standpoint’ stops meaning much. An attacker with the hardware in hand can extract the firmware, reverse engineer the protocol, and test fake alerts against the real thing until one works. Sensitive hardware will eventually leave your control, so you have to design as if it already has.”
“Re authentication: public emergency alerts don’t need to be secret, they need to be trustworthy. A receiver that can’t verify who sent a message will believe anyone with a transmitter. Digital signatures are a well-understood fix. Leaving them out of a system that can move an entire population was a design choice, not a technical limitation.
“The problem isn’t that J-Alert is unencrypted. It’s that it can’t tell the government’s warning from anyone else’s.”
Jacob Krell, Senior Director: Secure AI Solutions & Cybersecurity, Suzu Labs:
“A satellite link delivers data. It does not prove who sent it. If a receiver validates only the packet format, an attacker can impersonate the system from the ground.
“Japan’s J-Alert system exposes that gap. Kyodo reported that data sent through its satellite channel is unencrypted, and the receiver has no way to verify its source. Yudai Kirishiki of Unknown Technologies tested a receiver formerly used by a local government and found no electronic signature checks. The receiver accepted J-Alert-formatted data transmitted from an elevated location, such as a drone.
“Brazil had its own emergency-alert failure in June, when credentials tied to two Pará Civil Defense agents were used to send false alerts through the national platform to areas those accounts were not authorized to reach.
ㅤJapan and the rest of the world needs to figure this out. Unencrypted communications in 2026 are bad and need to be killed off quickly. Because this is a horrible place to be in.
From a Japanese cloud outage to Gorton’s parent company: the hidden supply chain risk for U.S. firms
Posted in Commentary with tags Japan on October 9, 2026 by itnerdA ransomware attack against a SoftBank-owned cloud provider in Japan has affected 495 companies and local governments, and the impact is expanding beyond the original infrastructure outage.
JR East has now disclosed approximately 6.09 million potentially exposed customer records across its group. Nissui, which operates major U.S. seafood businesses including Gorton’s, has confirmed disruptions to its Japanese logistics subsidiary. No direct U.S. disruption has been established.
The next development to watch is which additional customers disclose incidents as investigations continue.
John Watters, Founder & CEO, iCOUNTER | Former President & COO, Mandiant Said This:
“One ransomware attack against a cloud provider in Japan has put 495 companies and local governments at risk, with JR East already reporting approximately 6.09 million potentially exposed customer records. And this story is far from over. As more organizations investigate their exposure, we should expect additional disclosures that reveal just how far a single attack can reach.
This isn’t just a Japan problem. It’s a warning to American businesses about the dependencies hiding inside their supply chains. Nissui, one of the affected organizations, has significant U.S. operations, illustrating how interconnected these ecosystems have become, even though no impact on its American operations has been confirmed.
What concerns me most is that many organizations won’t know they’re exposed until a vendor tells them. By then, critical decisions about data protection, business continuity, and recovery may already be overdue.
Every CISO should be asking three questions right now: Which of our vendors and their suppliers depend on the affected infrastructure? Is our data exposed? And what is our response plan if those services go down?
Traditional third-party risk assessments tell you whether a vendor met security requirements at a point in time. They don’t tell you when that vendor, or a supplier behind it, is actively under attack.
The next breach notification shouldn’t be the first time you discover your organization was at risk. Security teams need to identify threats across their extended ecosystem, determine what matters to their business, and act before a supplier’s incident becomes their own.”
With everything being interdependent on everything else, you’re only as secure as the guy next to you. Thus need to make sure that the guy next to you is secure to your standards and not theirs.
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