Thursday, February 21, 2013

Poor man's browser sandboxing

Last update: Sat Feb 23 15:14:13 CET 2013

Nowadays I use my browser most of the time, as you probably do as well. And like me, you are probably quite annoyed to run this big software blob and its unavoidable bugs against so many websites. Yes, browsers are the prime attack vector now.

So why not sandbox it as another user so as to insulate it from you sensitive data (ssh keys/agent, files, ...)? You can do this in about 15 minutes. This is more a quick reminder for me than a full-fledged blog post, so the explanations and commands are a little terse. Adapt them to fit your need.

$ sudo adduser -m browser
$ sudo mkdir ~browser/.ssh
$ sudo cp ~/.ssh/ ~browser/.ssh/authorized_keys

# You should shut down your browsers before doing this.
$ sudo mkdir ~browser/.config
$ sudo cp -Rp ~/.config/google-chrome ~browser/.config/
$ sudo cp -Rp ~/.mozilla ~browser/
$ sudo chown -R browser ~browser

$ cat > bin/ << EOF
exec ssh -Xf browser@localhost "$@"
$ chmod +x bin/

# Be sure that your ~/bin belongs to your $PATH.
$ runasbrowser Xephyr :1
$ runasbrowser google-chrome


  • You will probably need to put user "browser" in a group to allow him to play music :).
  • I've got the idea of this here; you can see that the author did much more things than me to set this up. I'm not sure why it works for me with so few steps.