Hacker News Reader

Comment by Wowfunhappy | Hacker News Reader

I don't want to re-hash the discussion from down-thread [1], but I think this is important. If XP is behind a NAT firewall and the user is browsing the web via a modern build of Chromium, how exactly would a hacker take over the machine without a zero day?

1: https://news.ycombinator.com/item?id=39580985

View on HN

It sounds so dumb on surface that someone would go such a great length to try protect a vulnerable operating system for browsing by building a forked browser and not use a modern os such as arch/linux.

If you need access to legacy Windows software, this may not be an option. I know Wine has gotten a lot better in recent years, but it still isn't 100%. There are other options as well such as virtual machines, but these often come with worse hardware requirements.

I also think it's perfectly valid to just prefer the feel of one OS over another. We live so much of our lives in front of a computer, it is meaningful whether or not that OS brings you joy.

Probably through RCE-s in Windows XP’s TCP/IP stack implementation.

What CVE(s) in the TCP/IP could be used for this?

A quick search led me to CVE-2010-2568, which isn’t in TCP/IP[1], but is an RCE vulnerability that could be triggered by a website triggering a file download and the user later opening the folder with the downloaded file in Windows Explorer. Windows XP with Service Pack 3 is vulnerable.

[1]: The CVE database has to have the worst search out of all bug trackers I’ve ever used.

(I think using older versions of Windows is fine. But under no circumstances would I connect them to the internet.)

Right, but that requires downloading a file, which on an older OS you shouldn't do except from sources you absolutely trust.

I really don't think there's anything wrong with browsing the internet.

Downloading a file is something that happens automatically when you e.g. navigate (or are automatically redirected) to a link which is served with Content-Type of application/octet-stream. Example: <https://0x0.st/H7bb.bin>. If you don’t modify your browser somehow, it’s not something you as a user can protect yourself against.

Hmm. It looks like files with the .lnk or .pif file extension can only be downloaded on a user gesture: https://chromium.googlesource.com/chromium/src/+/39841e54180...

So it can't be done silently. Although, I do wish the type was marked "DANGEROUS" a la dll files.

Not that I'd recommend browsing on an older, unpatched OS, but the modification in question is easy, and IMO worth the extra single click or keypress it introduces in exchange for eliminating "drive-by downloads" from questionable sites.

Chrome: Settings → Downloads → check "Ask where to save each file before downloading".

Edge: Settings → Downloads → check "Ask me what to do with each download".

Firefox: Settings → General → under "Files and Applications", check "Always ask you where to save files".

Safari (macOS): Settings → General → as "File download location", choose "Ask for each download". While you're here, uncheck "Open “safe” files after downloading" (Apple scare quotes "safe" appropriately, yet AFAIK still enables this option by default, even after it's been a factor in multiple exploits over the years).

n-day in any part of the OS stack that the browser touches?

Reply on news.ycombinator.com