A privilege escalation from Chrome extensions (2023)
10 comments
·May 28, 2025Briannaj
curiousObject
Agree.
The only permission the extension needed was “downloads, which normally only allows an extension to download and search for user files, not read or write to them”
That’s not an unusual permission for an attractive but safe sounding extension, for example an extension to download all images from a page
$100k at least?
The value of this to bad guys could be up to millions
SchemaLoad
Well the author decided to sell the bug to Google rather than to criminals so I guess it was deemed a good value. By selling it to Google you get to write a nice blog post you can show to future employers and you don't have to involve yourself in crime. So the payout needed is a lot less than what hackers might be offering.
DaSHacka
I have to wonder how many people mix-and-match.
Like, does a 6th or 7th blog post really matter, versus getting a large payout?
No rule that says you can't do both, or only disclose+publish the more 'impressive' of your exploits.
tim1994
Interesting read for sure! This is about ChromeOS though, Chrome on other platforms was not affected.
rxliuli
Your journey of discovery is really cool.
rvz
> For example, Google awarded $10,000 to a bug report which showed that extensions could read local files by screenshotting them. But there are more dangerous things than file reads.
I think this researcher got scammed without knowing it.
Google paid $10k for this bug despite billions of users using Chrome and there are plenty of brokers that will pay much more than that. (e.g. Zerodium)
They should have sold it as a 0day on the black market for more that $250k.
This is worth more than 10k imo. But I guess since you have to have an extension installed maybe that's why?