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Re: CVE Request/Guidance: Linux kernel cdc-wdm buffer overflow triggered by device


From: Petr Matousek <pmatouse () redhat com>
Date: Thu, 14 Mar 2013 17:19:24 +0100

Hi Marcus,

On Thu, Mar 14, 2013 at 02:43:41PM +0100, Marcus Meissner wrote:
I am wondering ... do we consider attacks with special attack taylored USB
devices as CVE worthy?

There is only some precedence in the CVE DB, but not much.

I stumbled over this fix from one of my colleagues where a specifically
made USB device reporting the "cdc-wdm" USB class could cause a kernel
heap overflow.

"Malicious attached devices" might fall into several categories:

1. Attaching the device causes the issue directly within the kernel / autoloaded
   module, without user interaction. (here the case)


2. Attaching the device causes the issue when userspace, dependend on
   e.g. desktop system, does initiate a seperate action (like an automount
   and then exploitation of something) (so not direct a kernel, but a
   kernel + GNOME/KDE interaction).


3. User needs to do something with the attached device (like click on 
   a file on a USB disk)

I would consider (1) and (2) CVE worthy at least, not so sure with (3).

FWIW, I think all of the three options are CVE worthy. As Eugene said,
some filesystem bugs fall into (3) and they have been issued CVE
indentifiers.

-- 
Petr Matousek / Red Hat Security Response Team


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