Copy Link
Add to Bookmark
Report
CERT Advisory 101
-----BEGIN PGP SIGNED MESSAGE-----
=============================================================================
CERT(sm) Advisory CA-95:14
Original issue date: November 1, 1995
Last revised: August 30, 1996
Information previously in the README was inserted
into the advisory.
A complete revision history is at the end of this file.
Topic: Telnetd Environment Vulnerability
- -----------------------------------------------------------------------------
The CERT Coordination Center has been made aware of a vulnerability with
some telnet daemons. The daemons affected are those that support RFC 1408
or RFC 1572, both titled "Telnet Environment Option," running on systems
that also support shared object libraries.
To determine if your system is potentially vulnerable, refer to the
information we have received from vendors which is summarized in Section III
below; details are in Appendix A. Note that if you installed a version of
David Borman's telnet package that is older than October 23, 1995, your system
may be vulnerable even though it was not vulnerable as distributed by the
vendor.
If your vendor is not listed, you will need to determine if your system
may be vulnerable. First, determine if your telnet daemon is RFC 1408/1572
compliant. One indication that it is compliant is if your telnet(1)
program supports the "environ" command or your telnetd(8) program supports
the ENVIRON or NEW-ENVIRON options. Unless you are certain that your
telnet daemon is not RFC 1408/1572 compliant, you may wish to assume it is
to be safe. Second, determine if your system supports shared libraries. To
do this, consult the ld(1) manual page. If it describes dynamic or shared
objects, your system probably supports shared object libraries. A system
is potentially vulnerable if the telnet daemon supports RFC 1408/RFC 1572
and the system supports shared object libraries.
We recommend that you follow your vendor's directions for addressing this
vulnerability. Until you can install a patch, we recommend using the
workaround in Appendix B below. If you have previously installed David
Borman's telnet package on your system, we recommend that you obtain the
current version of telnet (see Section III.C).
We will update this advisory as we receive additional information.
Please check advisory files regularly for updates that relate to your site.
- -----------------------------------------------------------------------------
I. Description
Some telnet daemons support RFC 1408 or RFC 1572, both titled "Telnet
Environment Option." This extension to telnet provides the ability
to transfer environment variables from one system to another. If
the remote or targeted system, the one to which the telnet is
connecting, is running an RFC 1408/RFC 1572-compliant telnet daemon
*and* the targeted system also supports shared object libraries, then
it may be possible to transfer environment variables that influence
the login program called by the telnet daemon. By influencing that
targeted system, a user may be able to bypass the normal login and
authentication scheme and may become root on that system.
Users with accounts on the targeted system can exploit this
vulnerability. Users without accounts on that system can also
exploit this vulnerability if they are first able to deposit an
altered shared object library onto the targeted system. Therefore, a
system may be vulnerable to users with and without local accounts.
Not all systems that run an RFC 1408/RFC 1572-compliant telnet daemon
and support shared object libraries are vulnerable. Some vendors have
changed the trust model such that environment variables provided by
the telnet daemon are not trusted and therefore are not used by the
login program. Section III contains a summary of information vendors
have reported as of the date of this advisory.
II. Impact
Local and remote users can become root on the targeted system.
III. Solution
The general solution to this problem is to replace the telnet daemon
with one that changes the environment given to the login program. We
recommend that you install a patch from your vendor if possible. If this
is not possible, we recommend using the workaround in Appendix B until
you can install a patch. Finally, if you have previously installed Mr.
Borman's telnet package, see Section C for how to get a new version that
fixes the vulnerability.
A. Vendor Patches
Below is a summary of the vendors listed in Appendix A of this
advisory. More complete information, including how to obtain patches,
is provided in the appendix. We will update the appendix as we receive
more information from vendors.
If your vendor's name is not on this list, please contact the
vendor directly.
REMINDER: If you installed a version of David Borman's telnet package
that is older than October 23, 1995, your system may be
vulnerable even though it was not vulnerable as distributed
by the vendor.
Vendor or Source
----------------
Apple Computer
Berkeley Software Design
Cray Research
CYGNUS
Data General
Digital Equipment
FreeBSD
Harris
Hewlett-Packard
IBM Corp.
Linux
MIT-distributed for Athena
NEC
NetBSD
Open Software Foundation
OpenVision
SCO
SGI
Sony Corp.
B. Workaround
Until you can install a patch from your vendor, you can use
the workaround provided in Appendix B.
C. If you have installed a previous version of Mr. Borman's
telnet package, note that he has fixed this problem in
the version available at the following location:
ftp://ftp.cray.com/src/telnet/telnet.95.10.23.NE.tar.Z
MD5 checksum 2e14879a5b0aa6dd855a17fa8a3086cf
..............................................................................
Appendix A: Vendor Information
Below is information we have received from vendors. If you do not see your
vendor's name below, contact the vendor directly for information.
Apple Computer, Inc.
- --------------------
Apple's A/UX is not vulnerable.
Berkeley Software Design, Inc.
- -----------------------------
BSDI's BSD/OS is not vulnerable.
Cray Research, Inc.
- -------------------
Cray's UNICOS is not vulnerable.
CYGNUS Network Security V4 Free Network Release
- ----------------------------------------------------
cns-95q1 is vulnerable. cns-95q4 is not vulnerable.
Customers can use the following URL to obtain the patch:
http://www.cygnus.com/data/cns/telnetdpatch.html
If customers are unable to obtain the patch in this manner
or have any questions, send e-mail to kerbask@cygnus.com/
Note that while the URL and patch are already available, there
is no link to the page yet. We will add a link once the
announcement has been made.
Data General Corporation
- ------------------------
Data General believes the DG/UX operating system to be
NOT vulnerable to this problem. This includes all supported
releases, DG/UX 5.4 Release 3.00, DG/UX 5.4 Release 3.10,
DG/UX Release 4.10 and all related Trusted DG/UX releases.
Specifically, telnetd shipped in DG/UX does not support
environment options and does not support RFC 1572.
Digital Equipment Corporation
- -----------------------------
Digital's OSF/1: vulnerable
Digital's ULTRIX: not vulnerable
Digital has corrected this potential vulnerability. Patches containing
new images for Digital's OSF/1 platforms are being provided to your
normal Digital Support channels beginning October 31 (U.S. time). The
kits may be identified as ECO SSRT0367 (telnetd) for DEC OSF/1 V2.0
thru V3.2c
This potential vulnerability is not present on Digital's ULTRIX systems.
Digital distribution of this announcement will be via AES services (DIA,
DSNlink FLASH etc.). Digital Equipment Corporation strongly urges Customers
to upgrade to a minimum of DEC OSF/1 V3.0, then apply this patch.
FreeBSD
- -------
Vulnerable. A patch has been applied to the current development FreeBSD
source tree which is not yet released. This patch is slightly modified
compared to posted one, i.e. only variables which affects FreeBSD are
disabled. It is telnetd patch, not a login wrapper.
For the official patch, location please contact:
Jordan Hubbard <jkh@FreeBSD.org>
Harris
- ------
Harris Computer Systems Corporation's Night Hawk is not vulnerable.
Hewlett-Packard Company
- -----------------------
HP/UX is not vulnerable.
IBM Corporation
- ---------------
AIX is not vulnerable to this attack.
Linux (freely available software; not a vendor)
- -----
Debian GNU/Linux (From "Peter Tobias" <tobias@et-inf.fho-emden.de>):
The current version of the Debian GNU/Linux distribution (released 10/27/95)
is not vulnerable anymore. All Debian Installations that use a netstd
package version prior to v1.21-1 are vulnerable (telnetd is part of
the netstd package). netstd-1.21-1 and above are ok.
Patches are available. Peter fixed the bug last week and uploaded the
fixed version to our ftp site (ftp.debian.org). Binaries, sources and
the diffs against the bsd telnetd can be found there. The URL for the
new binary package is:
ftp://ftp.debian.org/debian/debian-0.93/binary/net/netstd-1.21-1.deb
and the sources and the diff against the bsd telnetd can be found at:
ftp://ftp.debian.org/debian/debian-0.93/source/net/netstd-1.21-1/telnetd.tar.gz
ftp://ftp.debian.org/debian/debian-0.93/source/net/netstd-1.21-1/telnetd.diff.gz
Red Hat Linux (From Erik Troan <ewt@redhat.com>):
Vulnerable. A fix is now available at:
ftp://ftp.redhat.com/pub/redhat-2.0/updates/NetKit-B-0.06-4.i386.rpm
ftp://ftp.pht.com/pub/linux/redhat/redhat-2.0/updates/NetKit-B-0.06-4.i386.rpm
It will also be fixed in the upcoming Red Hat 2.1 release.
Slackware Linux is vulnerable. The fixes are available from:
ftp://ftp.cymru.net/pub/linux/security/in.telnetd.bin.gz
MD5 (in.telnetd.bin.gz) = 300fc2b022f338e32db411d0e14f0bed
ftp://ftp.cymru.net/pub/linux/security/in.telnetd.bin.elf.gz
MD5 (in.telnetd.bin.elf.gz) = a9ed9a0b90b7a62c98c185e9c7970c5e
The CERT Coordination Center has received information that Paul Leyland
<plc@sable.ox.ac.uk> has placed patches for Linux on ftp.ox.ac.uk.
Non-US sites may want to obtain the patches from this archive for convenience.
However, please note that these patches will only be available for the next
few months; at some point they will be removed from this location.
Linux: This consists of a README, a patch for the telnetd source and a
compiled telnetd which should be ok for most Slackware distributions
and is available from
ftp://ftp.ox.ac.uk/pub/comp/security/software/patches/telnetd/linux
MD5 (envpatch) = 3dff044bae0ee7076b8dce735e174962
MD5 (telnetd) = ee2146342059ab00b94fae19f9b1ea63
MD5 (README) = 83f8d07a9b9e8f307346d2ac4b8b3f39
MIT-distributed Athena telnet/telnet95
- --------------------------------------
Vulnerable. Patches available in:
ftp://aeneas.mit.edu/pub/kerberos/telnet-patch/
beta4-3.patch is the patch versus the Beta 4 patch level 3 distribution
of Kerberos v5.
beta5.patch is the patch versus the Beta 5 distribution of Kerberos V5.
Both patches have been PGP signed by Ted Ts'o <tytso@MIT.EDU> using
detached signatures (beta4-3.patch.sig and beta5.patch.sig).
NEC Corporation
- ---------------
Some NEC systems are vulnerable. Here is their vulnerability matrix:
OS Version Status
- ------------------ ------------ -------------------------------------
EWS-UX/V(Rel4.0) R1.x - R6.x not vulnerable
EWS-UX/V(Rel4.2) R7.x - R10.x not vulnerable
EWS-UX/V(Rel4.2MP) R10.x vulnerable
patch available
UP-UX/V R2.x - R4.x not vulnerable
UP-UX/V(Rel4.2MP) R5.x - R7.x vulnerable
patch available
UX/4800 R11.x vulnerable
patch available
- --------------------------------------------------------------------------
The patches are available through anonymous FTP from
ftp://ftp.meshnet.or.jp in the /pub/48pub/security
directory. Please refer to the README file in the directory
concerning the appropriate patches that should be
retrieved.
OS Version Patch-ID and Checksums
------------------ ------- -------------------------------------------------
EWS-UX/V(Rel4.2MP) R10.x NECmas001
Results of sum = 760 295
MD5 (NECmas001.COM.pkg) = 588ED562BBDA6AFF45F1910A75C19B30
UP-UX/V(Rel4.2MP) R5.x NECu5s001
Results of sum = 22675 293
MD5 (NECu5s001.COM.pkg) = CBBA695079570BE994EDE8D5AD296B38
R6.x NECu6s001
Results of sum = 40159 293
MD5 (NECu6s001.COM.pkg) = C891AF03402CFD092B930253DC3CD607
R7.x NECu7s001
Results of sum = 65094 295
MD5 (NECu7s001.COM.pkg) = 00BAFAFF4A8FCFFB58FB6F8F94039D14
UX/4800 R11.x NECmbs002
Results of sum = 34536 295
MD5 (NECmbs002.COM.pkg) = E6ADAAC22C1B32C4180B855C19B49205
Contacts for further information:
E-mail:UX48-security-support@nec.co.jp
NetBSD
- ------
NetBSD 1.0 (the last official release) is vulnerable; NetBSD 1.1 (due
out in mid-November) will not be. NetBSD-current is not vulnerable,
as of a week or so ago.
Patches: A source form patch has been developed. A core team member will
have to make source and binary patches available and provide a location for
it.
The login-wrapper given in the advisory can be compiled with NetBSD with:
cc -static -o login-wrapper login-wrapper.c
Open Software Foundation
- ------------------------
OSF/1 version 1.3 is not vulnerable.
OpenVision
- ----------
This is from: Barry Jaspan <bjaspan@cam.ov.com>:
OpenVision has a patch for the telnetd in OpenV*Secure 1.2 and will
contact its customers directly.
The Santa Cruz Operation Inc.
- -----------------------------
SCO is NOT vulnerable.
Silicon Graphics
- ----------------
On November 16, 1995, Silicon Graphics updated their advisory,
19951101-02-P1010o1020, concerning the Telnetd vulnerability.
In the original advisory, 19951101-01-P1010o1020, the patches 1010 and
1020 were indicated for the wrong versions of IRIX. Patch 1010 is for
IRIX 6.1 and patch 1020 is for IRIX 5.2, 5.3, 6.0, 6.0.1. The
corrections have been made below.
The solution for this issue is a replacement of the telnetd program
for those versions that are vulnerable. The following patches have
been generated for those versions vulnerable and freely provides them
for the community.
**** IRIX 3.x ****
This version of IRIX is not vulnerable. No action is required.
**** IRIX 4.x ****
This version of IRIX is not vulnerable. No action is required.
**** IRIX 5.0.x, 5.1.x ****
For the IRIX operating systems versions 5.0.x, 5.1.x, an upgrade
to 5.2 or better is required first. When the upgrade is completed,
then the patches described in the next sections "**** IRIX 5.2, 5.3, 6.0,
6.0.1, 6.1 ***" or "**** IRIX 6.1 ****" can be applied.
**** IRIX 5.2, 5.3, 6.0, 6.0.1 ****
For the IRIX operating system versions 5.2, 5.3, 6.0, and 6.0.1,
an inst-able patch has been generated and made available via anonymous
ftp and/or your service/support provider. The patch is number 1020
and will install on IRIX 5.2, 5.3, 6.0 and 6.0.1 .
The SGI anonymous ftp site is sgigate.sgi.com (204.94.209.1). Patch
1020 can be found in the following directories on the ftp server:
~ftp/Security
or
~ftp/Patches/5.2
~ftp/Patches/5.3
~ftp/Patches/6.0
~ftp/Patches/6.0.1
The actual patch will be a tar file containing the following files:
Filename: README.patch.1020
Algorithm #1 (sum -r): 31057 8 README.patch.1020
Algorithm #2 (sum): 40592 8 README.patch.1020
MD5 checksum: 02F06ECD6240015F8DF82A99EC01E911
Filename: patchSG0001020
Algorithm #1 (sum -r): 07232 2 patchSG0001020
Algorithm #2 (sum): 47310 2 patchSG0001020
MD5 checksum: DA2341626FAEB9D67BA85FA3465BA9D9
Filename: patchSG0001020.eoe1_sw
Algorithm #1 (sum -r): 22449 62 patchSG0001020.eoe1_sw
Algorithm #2 (sum): 36518 62 patchSG0001020.eoe1_sw
MD5 checksum: 936019F2CC9AB6CAE0D2DF611D461475
Filename: patchSG0001020.eoe2_sw
Algorithm #1 (sum -r): 29899 43 patchSG0001020.eoe2_sw
Algorithm #2 (sum): 12088 43 patchSG0001020.eoe2_sw
MD5 checksum: 19A9C0BCB6F178E7EDF86850A1CF81D1
Filename: patchSG0001020.idb
Algorithm #1 (sum -r): 64615 2 patchSG0001020.idb
Algorithm #2 (sum): 46761 2 patchSG0001020.idb
MD5 checksum: 487831A62C61FEAF5797859CBC1F018C
**** IRIX 6.1 ****
For the IRIX operating system version 6.1, an inst-able patch has
been generated and made available via anonymous ftp and/or your
service/support provider. The patch is number 1010 and will
install on IRIX 6.1 .
The SGI anonymous ftp site is sgigate.sgi.com (204.94.209.1). Patch
1010 can be found in the following directories on the ftp server:
~ftp/Security
or
~ftp/Patches/6.1
The actual patch will be a tar file containing the following files:
Filename: README.patch.1010
Algorithm #1 (sum -r): 43949 8 README.patch.1010
Algorithm #2 (sum): 38201 8 README.patch.1010
MD5 checksum: A8781E18A1F79716FBFE0B6E083DAB31
Filename: patchSG0001010
Algorithm #1 (sum -r): 08656 2 patchSG0001010
Algorithm #2 (sum): 45506 2 patchSG0001010
MD5 checksum: 34CF7F63073C225AD76150A4088E76AB
Filename: patchSG0001010.eoe1_sw
Algorithm #1 (sum -r): 12843 65 patchSG0001010.eoe1_sw
Algorithm #2 (sum): 42034 65 patchSG0001010.eoe1_sw
MD5 checksum: 82B8D375ECBF58A08286D393CE3980E7
Filename: patchSG0001010.eoe2_sw
Algorithm #1 (sum -r): 01655 47 patchSG0001010.eoe2_sw
Algorithm #2 (sum): 19507 47 patchSG0001010.eoe2_sw
MD5 checksum: 1A5C5B5B84E0188A923C48419F716492
Filename: patchSG0001010.idb
Algorithm #1 (sum -r): 31514 2 patchSG0001010.idb
Algorithm #2 (sum): 46531 2 patchSG0001010.idb
MD5 checksum: 9540492FEB00D41281AAF90AC3F67FA9
SGI Security Information/Contacts:
For obtaining security information, patches or assistance, please
contact your SGI support provider.
If there are questions about this document, email can be sent to
cse-security-alert@csd.sgi.com .
For reporting *NEW* SGI security issues, email can be sent to
security-alert@sgi.com.
Sony Corporation
- ----------------
Sony's NEWS-OS 6.x is not vulnerable.
Sun Microsystems, Inc.
- ---------------------
The CERT Coordination Center has not received a report from Sun Microsystems
regarding this vulnerability. However, we believe that SunOS 4.x and Solaris
2.X are not vulnerable. Please contact Sun directly for more accurate
information. Sun Microsystems OS platforms can be made to be vulnerable if a
Borman telnet version prior to that dated October 23, 1995, is installed on
these systems.
..............................................................................
Appendix B: login-wrapper Workaround
The login-wrapper program shown below is meant to be executed just before
the distributed login program. The wrapper cleans specific variables from
the environment before invoking the distributed login program.
- ------------------------cut here--8<------------------------
/*
* This is a login wrapper that removes all instances of
* various variables from the environment.
*
* Note: this program must be compiled statically to be
* effective against exploitation.
*
* Author: Lawrence R. Rogers
*
* 10/25/95 version 1.1 Original version
* 10/26/95 version 1.2 ELF_ variables removed (Linux)
* 10/27/95 version 1.3 ELF_ changed to ELF_LD_
* Added AOUT_LD_ (Linux)
*
*/
#include <stdio.h>
#if !defined(_PATH_LOGIN)
# define _PATH_LOGIN "/bin/login.real"
#endif
main (argc, argv, envp)
int argc;
char **argv, **envp;
{
register char **p1, **p2;
for (p1 = p2 = envp; *p1; p1++) {
if (strncmp(*p1, "LD_", 3) != 0 &&
strncmp(*p1, "_RLD", 4) != 0 &&
strncmp(*p1, "LIBPATH=", 8) != 0 &&
strncmp(*p1, "ELF_LD_", 7) != 0 &&
strncmp(*p1, "AOUT_LD_", 8) != 0 &&
strncmp(*p1, "IFS=", 4) != 0 ) {
*p2++ = *p1;
}
}
*p2 = 0;
execve(_PATH_LOGIN, argv, envp);
perror(_PATH_LOGIN);
exit(1);
}
- ------------------------cut here--8<------------------------
The following two examples show how to compile the login-wrapper for SGI's
IRIX 5.3 and FreeBSD 2.x systems. The examples move the distributed login
program to a new location and install the wrapper in the standard location.
When executed, the wrapper first cleanses the environment and then calls
the relocated, distributed login program.
Note 1: The wrapper must be compiled statically. On SGI's IRIX system,
compiling statically requires that the non-shared versions of libraries
be installed. Consult your system documentation to determine how to do
this.
Note 2: You may need to change the _PATH_LOGIN variable to define where
the real login program resides on your system. On some systems, login
resides in /usr/bin/login.
Compiling for IRIX 5.3
- ----------------------
# uname -a
IRIX test 5.3 11091812 IP22 mips
# /bin/ls -l /usr/lib/iaf/scheme
- -rwsr-xr-x 1 root sys 65832 Sep 9 14:24 /usr/lib/iaf/scheme
# /bin/cc -non_shared -O -D_PATH_LOGIN=\"/usr/lib/iaf/scheme.real\" \
login-wrapper.c -o login-wrapper
# /bin/mv /usr/lib/iaf/scheme /usr/lib/iaf/scheme.real
# /bin/chmod 755 /usr/lib/iaf/scheme.real
# /bin/mv login-wrapper /usr/lib/iaf/scheme
# /bin/chmod 4755 /usr/lib/iaf/scheme
# /bin/chown root /usr/lib/iaf/scheme
# /bin/chgrp sys /usr/lib/iaf/scheme
# /bin/ls -lL /usr/lib/iaf/scheme /usr/lib/iaf/scheme.real
- -rwxr-xr-x 1 root sys 65832 Sep 9 14:24
/usr/lib/iaf/scheme.real
- -rwsr-xr-x 1 root sys 213568 Oct 30 08:42 /usr/lib/iaf/scheme
Compiling for FreeBSD 2.x
- -------------------------
# /bin/ls -lg /usr/bin/login
- -r-sr-xr-x 1 root bin 20480 Jun 10 20:00 /usr/bin/login
# /usr/bin/cc -D_PATH_LOGIN=\"/usr/bin/login.real\" -static \
-O login-wrapper.c -o login-wrapper
# /bin/mv /usr/bin/login /usr/bin/login.real
# /bin/chmod 555 /usr/bin/login.real
# /bin/mv login-wrapper /usr/bin/login
# /bin/chmod 4555 /usr/bin/login
# /usr/sbin/chown root.bin /usr/bin/login
# /bin/ls -lg /usr/bin/login /usr/bin/login.real
- -r-sr-xr-x 1 root bin 24885 Oct 25 22:14 /usr/bin/login
- -r-xr-xr-x 1 root bin 20480 Jun 10 20:00 /usr/bin/login.real
- ---------------------------------------------------------------------------
The CERT Coordination Center staff thanks Eric Halil of AUSCERT, Wolfgang
Ley of DFNCERT, and Sam Hartman of the MIT Kerberos Development team for
their support in responding to this problem.
- ---------------------------------------------------------------------------
If you believe that your system has been compromised, contact the CERT
Coordination Center or your representative in the Forum of Incident
Response and Security Teams (FIRST).
If you wish to send sensitive incident or vulnerability information to
CERT staff by electronic mail, we strongly advise that the email be
encrypted. The CERT Coordination Center can support a shared DES key, PGP
(public key available via anonymous FTP on info.cert.org), or PEM (contact
CERT staff for details).
Internet email: cert@cert.org
Telephone: +1 412-268-7090 (24-hour hotline)
CERT personnel answer 8:30 a.m.-5:00 p.m. EST(GMT-5)/EDT(GMT-4),
and are on call for emergencies during other hours.
Fax: +1 412-268-6989
Postal address: CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA 15213-3890
USA
CERT advisories and bulletins are posted on the USENET newsgroup
comp.security.announce. If you would like to have future advisories and
bulletins mailed to you or to a mail exploder at your site, please send mail
to cert-advisory-request@cert.org.
Past CERT publications, information about FIRST representatives, and
other information related to computer security are available for anonymous
FTP from info.cert.org.
Copyright 1995, 1996 Carnegie Mellon University
This material may be reproduced and distributed without permission provided it
is used for non-commercial purposes and the copyright statement is included.
CERT is a service mark of Carnegie Mellon University.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Revision history
Aug. 30, 1996 Information previously in the README was inserted
into the advisory.
Mar. 22, 1996 Appendix A, SGI - Modified information for Silicon Graphics.
Feb. 08, 1996 Appendix A, NEC - Added patch information.
Nov. 08, 1995 Appendix A, IBM - Added an entry for IBM.
Linux - Added information about Slackware Linux.
NetBSD - Corrected compilation instructions.
SCO - Noted SCO is not vulnerable.
SGI - Updated information.
Sun - Added an entry.
Nov. 08, 1995 Appendix B - Replaced IRIX 5.3 section with new material.
-----BEGIN PGP SIGNATURE-----
Version: 2.6.2
iQCVAwUBMiS63XVP+x0t4w7BAQECPgP+Pq98bUO6PMmHI/PZqZC7e4+A0EzXV3Xi
Qw+B4Pei+k2+2oEVuhl46QxnL1jNuYcRcjErqJeeZopxMIggKGprwZWgfW3zPjrq
lXBnrO98DmUUMzCccPLDtA3QYctiad6I/ZnInj/kI3nESnfl+QnXrMeekwndXLZV
rJM9+YnrJx0=
=oQOU
-----END PGP SIGNATURE-----
