oss-sec mailing list archives
Re: BadUSB discussion
From: gremlin () gremlin ru
Date: Fri, 8 Aug 2014 21:57:49 +0400
On 08-Aug-2014 09:21:02 -0700, Greg KH wrote:
Oh, and if you want, you can disable all USB devices on your Linux system by default, and only "authorize" them explicitly if you programatically think they should be enabled. We have had support in the kernel for that for years now, but very few people actually use it.I've faced that only once, and my solution was straightforward: those two servers were running a kernel built with only basic USB HID support (keyboard+mouse, IIRC) and without module load support. That appeared to be quite enough.That doesn't prevent any other USB HID device from being plugged in and instantly working. Which again, you can prevent if you want to, but no one seems to do that...
Hmmm... To avoid possible confusion: that was CONFIG_USB_KBD - "USB HIDBP Keyboard (simple Boot) support", and CONFIG_USB_HID was turned off.
So the tools to do this are already there, why aren't you using them? :)You could guess: sometimes I'm developing USB devices and have to test them. That formed a good habit of connecting my devices to a hub instead of directly to BB :-)A USB hub doesn't do anything special except slow things down and add complexity to the overall USB system, and does nothing for "security" at all.
Sometimes they may hang when plugged device misbehaviors. Pulling out the cable and then plugging it back resumes normal operation. With direct connection, I sometimes ended up with all USB devices being inaccessible. Now, I keep a mouse plugged into the hub to detect these situations. Look here, I had some experiments recently: Bus 002 Device 063: ID 05e3:0606 Genesys Logic, Inc. USB 2.0 Hub Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 064: ID 046d:c016 Logitech, Inc. Optical Wheel Mouse Device IDs tell us the hub was reset several times :-) -- Alexey V. Vissarionov aka Gremlin from Kremlin <gremlin ПРИ gremlin ТЧК ru> GPG: 8832FE9FA791F7968AC96E4E909DAC45EF3B1FA8 @ hkp://keys.gnupg.net
Current thread:
- Re: BadUSB discussion, (continued)
- Re: BadUSB discussion gremlin (Aug 08)
- Re: BadUSB discussion John Haxby (Aug 08)
- Re: BadUSB discussion Rich Felker (Aug 08)
- Re: BadUSB discussion Greg KH (Aug 08)
- Re: BadUSB discussion Willy Tarreau (Aug 09)
- Re: BadUSB discussion Yves-Alexis Perez (Aug 09)
- Re: BadUSB discussion Willy Tarreau (Aug 09)
- Re: BadUSB discussion gremlin (Aug 08)
- Re: BadUSB discussion Greg KH (Aug 08)
- Re: BadUSB discussion gremlin (Aug 08)
- Re: BadUSB discussion Greg KH (Aug 08)
- Re: BadUSB discussion gremlin (Aug 08)
- Re: BadUSB discussion (GalaxyMaster) (Aug 08)
- Re: BadUSB discussion gremlin (Aug 08)
- Re: BadUSB discussion Greg KH (Aug 08)
- Re: BadUSB discussion Greg KH (Aug 08)