Date: Mon, 28 Jan 2002 10:46:24 -0800 (PST)
From: SGI Security Coordinator <[email protected]>
To: [email protected]Subject: IRIX O2 video security issue
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______________________________________________________________________________
SGI Security Advisory
Title: IRIX O2 video security issue
Number: 20020103-01-I
Date: January 28, 2002
______________________________________________________________________________
SGI provides this information freely to the SGI user community for its
consideration, interpretation, implementation and use. SGI recommends
that this information be acted upon as soon as possible.
SGI provides the information in this Security Advisory on an "AS-IS" basis
only, and disclaims all warranties with respect thereto, express, implied
or otherwise, including, without limitation, any warranty of merchantability
or fitness for a particular purpose. In no event shall SGI be liable for
any loss of profits, loss of business, loss of data or for any indirect,
special, exemplary, incidental or consequential damages of any kind arising
from your use of, failure to use or improper use of any of the instructions
or information in this Security Advisory.
______________________________________________________________________________
- -----------------------
- --- Issue Specifics ---
- -----------------------
SGI has been informed of a security problem specific to video i/o on SGI O2
systems. When the vcp Default Input is set to "Output Video", a remote user
can log into the system, launch videoout and then videoin and can then see
what is happening on the screen of the remote system (reading mail, etc...).
This can be done regardless of xhosts or xauth settings on the remote
system.
SGI has investigated the issues and recommends the following steps for
neutralizing the exposure. It is HIGHLY RECOMMENDED that these measures be
implemented on ALL vulnerable SGI systems.
- --------------
- --- Impact ---
- --------------
This problem exists on all SGI O2 systems.
This vulnerability may be exploited by a local user, a local account is
required.
The exploitation of this vulnerabilitiy can lead to a root compromise.
- ------------------
- --- Workaround ---
- ------------------
There is as yet no patch that addresses this issue. You can work around
the problem by adding the following to /var/X11/xdm/Xstartup:
#
# Set the permissions of /dev/mvp so only the console user has access
#
if [ -r /dev/mvp ]; then
chown $USER /dev/mvp
chmod 600 /dev/mvp
fi
Add the following to /var/X11/xdm/Xreset:
#
# Reset the permissions on /dev/mvp
#
if [ -r /dev/mvp ]; then
chown root /dev/mvp
chmod 666 /dev/mvp
fi
These modifications change the ownership of the mvp device when a user logs
in and back out. When the device is owned by the user with 600 permissions,
nobody else is able to execute vcp, videoin, or videoout. Thus nobody can
see what's on the console of the system.
The /dev/mvp device only exists on O2s, so this problem does not impact
other IRIX platforms (Octane, Onyx, etc.)
After these modifications have been made, it is also not possible to login
remotely and access other video signals.
- ----------------
- --- Solution ---
- ----------------
SGI has not released a patch for this issue. Please follow the workaround
instructions above.
- -------------------
- --- Information ---
- -------------------
SGI Security Advisories can be found at:
http://www.sgi.com/support/security/ and
ftp://patches.sgi.com/support/free/security/advisories/
SGI Security Patches can be found at:
http://www.sgi.com/support/security/ and
ftp://patches.sgi.com/support/free/security/patches/
SGI patches for IRIX can be found at the following patch servers:
http://support.sgi.com/irix/ and ftp://patches.sgi.com/
SGI freeware updates for IRIX can be found at:
http://freeware.sgi.com/
SGI fixes for SGI open sourced code can be found on:
http://oss.sgi.com/projects/
SGI patches and RPMs for Linux can be found at:
http://support.sgi.com/linux/ or
http://oss.sgi.com/projects/sgilinux-combined/download/security-fixes/
SGI patches for Windows NT or 2000 can be found at:
http://support.sgi.com/nt/
IRIX 5.2-6.4 Recommended/Required Patch Sets can be found at:
http://support.sgi.com/irix/ and ftp://patches.sgi.com/support/patchset/
IRIX 6.5 Maintenance Release Streams can be found at:
http://support.sgi.com/colls/patches/tools/relstream/index.html
IRIX 6.5 Software Update CDs can be obtained from:
http://support.sgi.com/irix/swupdates/
The primary SGI anonymous FTP site for security advisories and patches is
patches.sgi.com (216.32.174.211). Security advisories and patches are
located under the URL ftp://patches.sgi.com/support/free/security/
For security and patch management reasons, ftp.sgi.com (mirrors
patches.sgi.com security FTP repository) lags behind and does not do a
real-time update.
- ------------------------
- --- Acknowledgments ----
- ------------------------
SGI wishes to thank the SGI customer who discovered this vulnerability and
the users of the Internet Community at large for their assistance in this
matter.
- -----------------------------------------
- --- SGI Security Information/Contacts ---
- -----------------------------------------
If there are questions about this document, email can be sent to
[email protected].
------oOo------
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------oOo------
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------oOo------
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------oOo------
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______________________________________________________________________________
This information is provided freely to all interested parties
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