How do Random Credentials Mysteriously Appear?

One commonly-reported issue to browsers’ security teams sounds like: “Some random person’s passwords started appearing in my browser password manager?!? This must be a security bug of some sort!” This issue has been reported dozens of times, and it’s a reflection of a perhaps-surprising behavior of browser login and sync. So, what’s happening? Background EvenContinue reading “How do Random Credentials Mysteriously Appear?”

Attack Techniques: Spoofing via UserInfo

I received the following phishing lure by SMS a few days back: The syntax of URLs is complicated, and even tech-savvy users often misinterpret them. In the case of the URL above, the actual site’s hostname is, and the misleading text is just a phony username:password pair making up the UserInfo component ofContinue reading “Attack Techniques: Spoofing via UserInfo”

Revealing Passwords

The Microsoft Edge browser, Edge Legacy, and Internet Explorer all offer a convenient mechanism for users to unmask their typing as they edit a password field: Clicking the little eye icon disables the masking dots so that users can see the characters they’re typing: This feature can be very useful for those of us whoContinue reading “Revealing Passwords”

Browser Password Managers: Threat Models

All major browsers have a built-in password manager. So we should use them, right? I Do Should You? The easy answer is “Yes, use your browser’s password manager!“ The more nuanced answer begins: “Tell me about your threat model?” As when evaluating almost any security feature, my threat model might not match your threat model,Continue reading “Browser Password Managers: Threat Models”

Stealing your own password is not a vulnerability

By far, the most commonly-reported “vulnerability” reported to the Chrome Vulnerability Rewards program boils down to “I can steal my own password.” Despite having its very own FAQ entry, this gets reported to the VRP at varying levels of breathlessness, sometimes multiple times per day. You can see this “attack” in action: Yes, it’s true,Continue reading “Stealing your own password is not a vulnerability”