Just a lvl 27 guy from 🇫🇮 Finland. Full-stack web developer and Scrum Master by trade, but more into server-side programming, networking, and sysadmin stuff.

During the summer, I love trekking, camping, and going on long hiking adventures. Also somewhat of an avgeek and a huge Lego fanatic.

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Joined 2 years ago
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Cake day: June 20th, 2023

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  • They can include runnable JavaScript too, which can cause vulnerabilities in certain contexts. One example from work some years back: We had a web app where users could upload files, and certain users could view files uploaded by others. They had the option to download the file or, if it was a file type that the browser could display (like an image or a PDF), the site would display it directly on the page.

    To prevent any XSS (scripts from user-provided files), we served all files with the CSP sandbox header, which prevents any scripts from running. However, at the time, that header broke some features of the video player on certain browsers (I think in Safari, at least), so we had to serve some file types without the header. Mistakenly, we also included image files in the exclusion, as everyone through image files couldn’t contain scripts. But the MIME type for SVG files is image/svg+xml… It was very embarrassing to have such a simple XSS vuln flagged in a security audit.










  • There would need to be a way to guarantee that only the browser could do this, or at least some way to tell exactly what the source was.

    I don’t think there’s a way to do that. Let’s say browsers implemented this. I could then just take a copy of Firefox source code and make my own version, which is exactly the same than normal FF except the fancy screenshot tool has been slightly modified to allow editing the page before taking the screenshot.


  • The website (Telegram in this case, but can be any website) adds a specifically crafted text to the clipboard and then tricks the user into pasting that text into the Windows Run dialog, which can be used to execute any command(s), basically like a command prompt.

    The text the attacker places in the clipboard is actually a command to download and execute an executable file from the internet, giving the attacker remote access to the system or whatever the payload happens to be.

    It’s a pretty clever trick. Perhaps MS should consider adding a warning before allowing pasting into the Run dialog or cmd for the first time. They already have this in the Edge browser console.






  • The original Super Mario Bros. and SMB 3. The first console I got to play as a child was the NES at my grandparents’ house. Every couple of years I get a nostalgic craving and it’s usually those two games I return to. Also, there are many great rom hacks available if getting bored of the originals.