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Let's build a Chrome extension that steals as much data as possible

mattfrisbie.substack.com

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Re: Let's build a Chrome extension that steals as much data as possible

#3
This is an excellent accidental rebuttal to the entire Manifest v3 project. The stated reason for the new major version and breaking changes is officially:

> Manifest V3 represents one of the most significant shifts in the extensions platform since it launched a decade ago. Manifest V3 extensions enjoy enhancements in security, privacy, and performance...

https://developer.chrome.com/docs/extensions/mv3/intro/

Web developers (see uBlock origin for one) have been complaining that Manifest v3 breaks chrome extensions for no discernible benefit and Manifests v3 exists entirely to protect Google's ad business. This review gives fresh evidence to support that assertion and showcases Google's deception. As seen in this blog post, extensions can request literally every permission and the user permission warning actively hides the permissions beyond the content fold.These changes haven't been made for security's sake.

I wish the entire Manifest v3 was scrapped, but that likely won't happen. I'll settle for people assuming Google is lying by default.

Re: Let's build a Chrome extension that steals as much data as possible

#5
post #2

Yea Chrome would be a lot more secure if we didn't let anyone view any data at all.

Just the title of this post alone should make it more than obvious that the article is not about preventing anyone to view data, but rather to grant anyone access to it in an exploitative way.

In response to the article itself: you might even be able to get such an extension on the Firefox Extensions store and just maybe get a "Recommended" status too. Refer to my comment in another post from a few days ago for other such current violations: https://news.ycombinator.com/item?id=34832280

Re: Let's build a Chrome extension that steals as much data as possible

#6
post #3

This is an excellent accidental rebuttal to the entire Manifest v3 project. The stated reason for the new major version and breaking changes is officially: > Manifest V3 represents one of the most significant shifts in the extensions platform since it launched a decade ago. Manifest V3 extensions enjoy enhancements in security, privacy, and performance... https://developer.chrome.com/docs/extensions/mv3/intro/ Web de…

The counterpoint might be that being declarative it's easier to do static analysis to find malicious extensions. But I'm not sure how much I buy that argument, and it's no excuse to disable v2 extensions entirely.

Re: Let's build a Chrome extension that steals as much data as possible

#7
The author notes that this sort of extension would be laughed out of the review queue....but there are plugin authors who get plenty of users by putting up a website and making the plugin available directly from their site.

For example, the author of FB Purity hasn't explained to anyone why his plugin is not available via Firefox's extension store, only via his page. Presumably, he didn't meet some requirements they had...but he won't say what they were...

Re: Let's build a Chrome extension that steals as much data as possible

#9
> Chrome scrolls the permission warning message container, so more than half of the warning messages don’t even show up. I’d bet most users wouldn’t think twice about installing an extension that appears to ask for just 5 permissions.

An egregious and nearly unbelievable oversight on Google's part. :-\

As a developer, it's unimaginable to me to not test the extreme high and low numbers of inputs cases to ensure things look and operate as expected. Especially for a security sensitive UI element.

The chain of humans who've been responsible for developing and testing Chrome Extension functionality and security has been asleep at the wheel this whole time, for something like 15 years.

There are so many risk-reduction controls in place; tons of red tape and umpteen security and privacy reviews required to ship even minor features or updates, yet here we are.

How many hands have been in the pot and not noticed/raised/resolved what amounts to a pretty obvious security vulnerability? And if this kind of issue can fly undetected for so long, what can organizations with drastically less resources than $GOOG do to ensure adequate velocity while not leaving the proverbial barn doors open?

The author deserves the highest tier of bug bounty reward for bringing this to light. What's that? It wasn't submitted through the proper channels to be eligible? Right.

Re: Let's build a Chrome extension that steals as much data as possible

#10
post #3

This is an excellent accidental rebuttal to the entire Manifest v3 project. The stated reason for the new major version and breaking changes is officially: > Manifest V3 represents one of the most significant shifts in the extensions platform since it launched a decade ago. Manifest V3 extensions enjoy enhancements in security, privacy, and performance... https://developer.chrome.com/docs/extensions/mv3/intro/ Web de…

It's good that it doesn't pretend to be a rebuttal, because it'd be a bad one.

I'm pretty sure the point of making a declarative content blocking API for adblockers is not to block all possible ways of writing a malware extension. It is just to make the most popular category of extensions safe by design. Once that has been done, it's then much easier to improve the situation with the remaining niche use cases.

What would those improvements look like? It could be finding other common ways of dangerous permissions being used by legit extensions, and extracting these patterns out as explicit and safe capabilities. It could be changing the messaging to make it easier for users to understand how dangerous the requested permission is (which they can't reasonably do while those dangerous permissions are still used by adblockers!). Or it could be a stricter review process for any extensions needing such permissions.

This extension that the author themselves think would never pass review doesn't really rebut that in any way.

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