Lizzie Dixon writes: > Hi, > > On 10/11, Christopher Allan Webber wrote: >> The default in Guile has been to expose a port over localhost to which >> code may be passed. The assumption for this is that only a local user >> may write to localhost, so it should be safe. Unfortunately, users >> simultaneously developing Guile and operating modern browsers are >> vulnerable to a combination of an html form protocol attack [1] and a >> DNS rebinding attack [2]. How to combine these attacks is published in >> the article "How to steal any developer's local database" [3]. > >> >> In Guile's case, the general idea is that you visit some site which >> presumably loads some javascript code (or tricks the developer into >> pressing a button which performs a POST), and the site operator switches >> the DNS from their own IP to 127.0.0.1. Then a POST is done from the >> website to 127.0.0.1 with the body containing scheme code. This code is >> then executed by the Guile interpreter on the listening port. > > You don't need to rebind DNS to exploit this bug, or other bugs like > it. I wrote some details here: > > <https://blog.lizzie.io/exploiting-CVE-2016-8606.html> > > Best, > > Lizzie.
Hi Lizzie! Thanks for the post. Interesting to see you figured out how to do it with a GET request, not just a POST. So, I guess this will work from a public site as well? I'm always a bit fuzzy about what browsers do and don't allow, but I'm stunned that a browser will let a request from some http://foo.example/ to http://localhost:37146/, even for just a GET. It seems like there are all sorts of daemons you can exploit that way. Anyway, thanks for the interesting blogpost, and kudos for using Guile to write your example! - Chris
