Description
OpenBSD and NetBSD permit usermode code to kill the display server and write to the X.Org /dev/xf86 device, which allows local users with root privileges to reduce securelevel by replacing the System Management Mode (SMM) handler via a write to an SMRAM address within /dev/xf86 (aka the video card memory-mapped I/O range), and then launching the new handler via a System Management Interrupt (SMI), as demonstrated by a write to Programmed I/O port 0xB2.
References (6)
Core 6
Core References
Third Party Advisory, VDB Entry mailing-list
x_refsource_bugtraq
http://www.securityfocus.com/archive/1/454510/100/0/threaded
Various Sources mailing-list
x_refsource_mlist
http://lists.freedesktop.org/archives/xorg/2004-June/000927.html
Third Party Advisory, VDB Entry mailing-list
x_refsource_bugtraq
http://www.securityfocus.com/archive/1/454706/100/0/threaded
Various Sources x_refsource_misc
http://www.ssi.gouv.fr/fr/sciences/fichiers/lti/cansecwest2006-duflot-paper.pdf
Various Sources x_refsource_misc
http://www.cansecwest.com/slides06/csw06-duflot.ppt
Third Party Advisory, VDB Entry mailing-list
x_refsource_bugtraq
http://www.securityfocus.com/archive/1/454379/100/0/threaded
Scores
EPSS
0.0005
EPSS Percentile
15.1%
Details
Status
published
Products (2)
netbsd/netbsd
2.0.4
openbsd/openbsd
Published
Dec 26, 2006
Tracked Since
Feb 18, 2026