oss-sec mailing list archives

Re: with firefox on X11, any page can pastejack you anytime


From: niekt0 <niekt0 () kyberia cz>
Date: Thu, 19 Oct 2023 22:35:54 +0200

Hi,

On Thu, Oct 19, 2023 at 05:04:10PM +0100, Sam Bull wrote:
On Wed, 2023-10-18 at 13:25 -0500, Grant Taylor wrote:
I think that this is more a problem with X11 security than it is a 
problem specific to Mozilla / Firefox.

Also a problem with shell security. If you paste something with line breaks into bash, it
executes them. If you paste the same into fish, it doesn't (it'll display the multi-line
input and expect you to hit the enter key to execute it as a command).

the problem with modification of "clipboard" is unfortunately much broader, than just command execution in the shell. 
Imagine situation like pasting a bank account number for money transfer into internetbankig web page, and some browser 
tab in background silently replaces the number. Or replaces the bitcoin address, to make situation more dramatic. The 
direct command execution is probably the most straight-forward approach, but with bit of a creativity you can come with 
many various attack scenarios. 

While I agree that application isolation in X11 is a security problem, this bug/feature is bit of a new pokemon, it 
also breaks tab isolation within a browser itself, when used under X11.

n.


Current thread: