- From: Phillip Hallam-Baker <hallam@gmail.com>
- Date: Wed, 25 Jul 2012 20:13:36 -0400
- To: James French <jfrench@denirostaff.com>
- Cc: "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
As I said, if the content type matters then it really needs to be considered a part of the content rather than something that intermediaries have a right to meddle with. Similarly, if A passes a message to B which 'modifies it' and then passes 'the message' to C, well, it isn't there are two completely separate messages from a security point of view, one between A-B and a second completely different set of content between B-C. The only way that a message can flow through B with 'modification' in a meaningful sense is if the message is a composite message and the parts that have been modified are separated from the parts that remain constant. So for example, I submit a purchase order to the local enterprise service which appends a second message with a promise of payment. The vendor receives two separate signed blobs, one for the bill of goods, another for the payment promise. On Wed, Jul 25, 2012 at 6:41 PM, James French <jfrench@denirostaff.com> wrote: > It occurs to me that a man-in-the-middle could change a Content-Type > header to trick a web service into a delivering scripted data. > > 1.) MITM uploads script.jpg to https2://legit-host/script.jpg > 2.) Client requests /script.jpg from legit-host > 3.) legit-host signs and delivers script.jpg with a Content-Type of: image/jpg > 4.) MITM changes Content-Type header from image/jpg to text/html > 5.) Client runs script.jpg with the permissions level of a script > running on legit-host > > It's unlikely that this scenario would come up in practice, but it > does exist as a hypothetical vector. > > On Wed, Jul 25, 2012 at 9:59 AM, Phillip Hallam-Baker <hallam@gmail.com> wrote: >> >> >> 3) HTTP security controls should only secure content. Signing headers >> is not only difficult, it is often counterproductive. If a Web service >> depends on information in a header there is probably something wrong >> -- Website: http://hallambaker.com/
Received on Thursday, 26 July 2012 00:14:03 UTC