Author Archives: ericlaw

Browser Security Bugs that Aren’t: JavaScript in PDF

A fairly common security bug report is of the form: “I can put JavaScript inside a PDF file and it runs!” For example, open this PDF file with Chrome, and you can see the alert(1) message displayed: Support for JavaScript within PDFs is by-design and expected by the developers of PDF rendering software, including commonContinue reading “Browser Security Bugs that Aren’t: JavaScript in PDF”

Attacker Techniques: Gesture Jacking

A few years back, I wrote a short explainer about User Gestures, a web platform concept whereby certain sensitive operations (e.g. opening a popup window) will first attempt to confirm whether the user intentionally requested the action. As noted in that post, gestures are a weak primitive — while checking whether the user clicked orContinue reading “Attacker Techniques: Gesture Jacking”

pushState and URL Blocking

The Web Platform offers a handy API called pushState that allows a website’s JavaScript to change the URL displayed in the address bar to another URL within the same origin without sending a network request and loading a new page. The pushState API is handy because it means that a Web Application can change theContinue reading “pushState and URL Blocking”

Browser Extensions: Powerful and Potentially Dangerous

Regular readers of my blogs know that I love browser extensions. Extensions can make using your browser more convenient, fun, and secure. Unfortunately, extensions can also break web apps in bizarre or amusing ways, dramatically slow your browser performance, leak your personal data, or compromise your device. The designers of the Chromium extension system createdContinue reading “Browser Extensions: Powerful and Potentially Dangerous”

Second Seaside Half

I ran my second Galveston Half Marathon on Sunday, February 25th. The course was identical to last year’s race, starting at Stewart beach heading north before looping back down to the Pleasure Pier before returning to the start/finish line on the beach. I opened hard, leaving with the 1:52 pacer and running with the 1:45Continue reading “Second Seaside Half”

The Importance of Feedback Loops

This morning, I found myself once again thinking about the critical importance of feedback loops. I thought about obvious examples where small bad things can so easily grow into large bad things: – A minor breach can lead to complete pwnage.– A small outbreak can become a pandemic.– A brush fire can spark a continentalContinue reading “The Importance of Feedback Loops”

Cloaking, Detonation, and Client-side Phishing Detection

Today, most browsers integrate security services that attempt to protect users from phishing attacks: for Microsoft’s Edge, the service is Defender SmartScreen, and for Chrome, Firefox, and many derivatives, it’s Google’s Safe Browsing. URL Reputation services do what you’d expect — they return a reputation based on the URL, and the browser will warn/block loadingContinue reading “Cloaking, Detonation, and Client-side Phishing Detection”