Abusing of Protocols to Load Local Files, bypass the HTML5 Sandbox, Open Popups and more

On October 25th, the fellows @MSEdgeDev twitted a link that called my attention because when I clicked on it (being on Chrome) the Windows Store App opened. It might not surprise you, but it surprised me! As far as I remembered, Chrome had this healthy habit of asking the user before opening external …

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Bypassing Mixed Content Warnings – Loading Insecure Content in Secure Pages

There are no doubts that the web is moving forward to HTTPS (secure) content. Most important names have today their certificates ready and their websites are in effect, secure. But have you ever wandered: secure to what extent? It’s clear that content served through HTTPS is protected from man in …

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Detecting Local Files to Evade Analysts

Last month we’ve been looking at how attackers were targeting unsavvy users by checking the associated mimeTypes to applications on the system. If the PC had analyst tools installed, something detected from withing the browser, then the malware refused to download the bad bits staying below the radars for a …

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On Patching Security Bugs

Hello fellow bug hunter! I want to share with you my thoughts on a slight change that the folks at Microsoft could embrace to make security better. This change, in my opinion, will make the security process more transparent for all, attracting bug hunters and making the lives of the bad guys more …

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Workers SOP Bypass importScripts and baseHref

As we know, all browsers impose several restrictions when trying to access resources from different origins. Of course we can play music and render images coming from different domains but thanks to the Same Origin Policy, we will not be able to read the content of those resources. For example, we can draw …

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Detecting analysts before installing the malware

With the help of a beautiful piece of code, malware authors can detect installed applications straight from within the browser and serve the bad bits only to unsavvy users. In other words, attackers target regular users by detecting specific analysts applications (like Fiddler) and serving their harmful program to users that do not have those apps …

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Referer spoofing and defeating the XSS filter

According to Wikipedia, “Referer spoofing is the sending of incorrect referer information in an HTTP request in order to prevent a website from obtaining accurate data on the identity of the web page previously visited by the user.” In other words, making a server think that requests are coming from anywhere we want. Referer …

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CSS History Leak or “I know where you’ve been”

Hello fellow bug hunter! I’ve been thinking this morning on the classic trick originally discovered by Jeremiah Grossman back in 2006, where you could find out which sites were visited by the user. If you are not familiar with this beauty, I recommend you reading his original post. I will do my best to quickly …

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Grabbing data from Inputs and Textareas

Both Microsoft Edge and Internet Explorer suffer from navigation problems, failing to keep up with the most updated history information. A framed navigation confuses these browsers and what seems to be a naive functionality problem ends up being a security bug: information disclosure across origins. Let’s first examine the functionality problem by building a …

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