Scott Helme

  1. Eight Bits of Trust; eMudhra's CA keys cracked in milliseconds

    One of eMudhra's certificate authority private keys is the number 4.Not a number that starts with 4, or the number 4 followed by a few hundred random digits, just, 4... Another one is 56, and another is 115. I know, because I recovered all of them from

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  2. Passkeys Are Not a Trap

    A post called Passkeys are a trap. Do not use them. has been doing the rounds over the last few days, making it pretty high on Hacker News, and I've had it sent to me many times with an 'is this true?' kind of vibe. It&

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  3. The First Reduction in Their History: 64-Day Let's Encrypt Certificates

    I remember being in the room at DEF CON 23 in Las Vegas, in 2015, listening to "Let's Encrypt – Minting Free Certificates to Encrypt the Entire Web". It was still months before Let's Encrypt would launch their public beta and begin cementing 90-

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  4. No Hacking Required: The Manchester Airports Group Data Breach

    On 27 August 2026, Manchester Airports Group told customers that "an unauthorised third party" had stolen their data. Car park bookings, lounge bookings, Fast Track purchases for airport security and passport control, along with airport WiFi sign-ups across Manchester, Stansted and East Midlands. Roughly…

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  5. The ultimate road trip combo: Starlink Mini + UniFi Travel Router

    I recently went on an epic road trip around Europe, covering 1,645 miles (2,647 km), and we took in some amazing sights and locations. As a tech geek, I was worried about my connectivity on the trip, so before we set off, I came up with a plan!

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  6. Introducing dbsc.dev: Does Your Browser Support DBSC?

    Every other web platform feature I've ever written about, I've been able to test in some easy way. Open DevTools, type the name of the thing, see if it's there. Device Bound Session Credentials doesn't work like that: there is no way

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  7. Device Bound Session Credentials lands in Chrome on macOS

    Device Bound Session Credentials (DBSC) is Chrome's answer to session cookie theft, usually by InfoStealer malware. Instead of a cookie being a bearer token that works anywhere it's pasted, DBSC binds the session to a private key that lives in your device's hardware and

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  8. Everything I Learned Shipping Device Bound Session Credentials

    We shipped Device Bound Session Credentials at Report URI, open-sourced the server-side implementation, and then discovered a long list of things the specification doesn't prepare you for.Some caused random logouts. One could deadlock a browser tab indefinitely. Two silently turned a device-bound session…

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  9. Connection Allowlist: a network firewall, built into the browser

    Connection Allowlist is a new browser security mechanism that lets a document declare, up front, the exact set of destinations it's permitted to open network connections to. Anything not on the list is blocked by the browser before the connection leaves the machine. It's currently a

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  10. Top 1 Million Analysis – June 2026: The State of Crypto

    This is part two of the ten-year anniversary Top 1 Million Analysis. Part one covered the broad state of the web — HTTPS, the security headers, cookies, email and DNS hygiene. This part is the bit I've been most excited to write: a focused look at the

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  11. Top 1 Million Analysis – June 2026: Ten Years of Web Security

    It's been a long time since the last one of these! The previous Top 1 Million Analysis was way back in June 2022, and a lot has happened since then. But there's a much bigger reason to dust off the crawler and publish another report: this

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  12. A dead CDN, a wildcard, and an attack waiting to happen: the netdna-ssl.com takeover

    Every now and then I go digging through Report URI's Threat Intelligence data feeds, looking for domains that show up in CSP reports where they really shouldn't. Last week one jumped out at me: netdna-ssl.com. If you've been around the WordPress world

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  13. Why No Passkeys? Naming the Top Sites That Still Don't Support Them

    Back in 2017, Troy Hunt and I built a little website called whynohttps.com. The idea was simple: take the most popular sites on the internet, check which ones still weren't redirecting visitors to HTTPS, and put the laggards on a list for everyone to see. No lecture,

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  14. The Instructure Canvas Breach (2026): How XSS in a Support Ticket Compromised 275 Million Students

    A single support ticket became the front door to 275 million student records. The Canvas breach shows how quickly untrusted user content can become a serious security incident when it is rendered inside privileged internal tooling. This was not an exotic attack chain; it was stored XSS, over-scoped access…

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  15. Open-Sourcing dbsc-php: a Server Library for Device Bound Session Credentials in PHP

    We’ve open-sourced dbsc-php, a small PHP library that makes it easier to deploy Device Bound Session Credentials and turn stolen session cookies into something far less useful. It's MIT-licensed, pure-PHP, and available on Packagist now!What is DBSC?If you'd

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