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/* *\
/ * * \
/ * * \
/ * * \
/ * System Vulnerabilities * \
| * * |
| * * |
| * * |
| * Another Modernz Presentation * |
| * * |
\ * by * /
\ * Multiphage * /
\ * * /
\ * (C)opyright June 9th, 1992 * /
\ * */
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The Modernz can be contacted at:
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IBM is aware of this problem and a fix is available as apar number "ix22628".
This patch is available for all AIX releases from "GOLD" to the current
release.
NOTE: THIS IS AN UPDATED PATCH FROM ONE RECENTLY MADE AVAILABLE and fixes
a security hole in the original patch. The SCCS id of the correct patch
is tftpd.c 1.13.1.3 (*not* 1.13.1.2 or earlier versions). This can be
checked using the following "what" command.
.More..
% what /etc/tftpd
/etc/tftpd:
56 1.13.1.3 tftpd.c, tcpip, tcpip312 10/10/91 09:01:48
tftpsubs.c 1.2 com/sockcmd/tftpd,3.1.2,9048312 10/8/89 17:40:55
IBM customers may call IBM Support (800-237-5511) and ask that the fix
be shipped to them. The fix will appear in the upcoming 2009 update
and the next release of AIX.
---------------------------------------------------------------------------
I. Description
Previous versions of tftpd did not provide a method for restricting
TFTP access.
II. Impact
If TFTP is enabled at your site, anyone on the Internet can retrieve
copies of your site's world-readable files, such as /etc/passwd.
III. Solution
A. Sites that do not need to allow tftp access should disable it.
This can be done by editing /etc/inetd.conf and deleting or
commenting out the tftpd line:
#tftp dgram udp wait nobody /etc/tftpd tftpd -n
and then, as root, restarting inetd with the "refresh" command.
# refresh -s inetd
For more details on starting/stopping tftp, refer to documentation
for the System Resource Controller (SRC) or the System Management
Interface Tool (SMIT).
B. Sites that must run tftpd (for example, to support X terminals)
should obtain and install the above patch AND create a
/etc/tftpaccess.ctl file to restrict the files that are accessible.
The /etc/tftpaccess.ctl file should be writable only by root.
Although the new /etc/tftpaccess.ctl mechanism provides a very general
capability, the CERT/CC strongly recommends that sites keep this
control file simple. For example, the following tftpaccess.ctl file
is all that is necessary to support IBM X terminals:
# /etc/tftpaccess.ctl
# By default, all files are restricted if /etc/tftpaccess.ctl exists.
# Allow access to X terminal files.
allow:/usr/lpp/x_st_mgr/bin
NOTE: Be CERTAIN to create the /etc/tftpaccess.ctl file.
If it does not exist then all world-readable files are accessible
as in the current version of tftpd.
Installation Instructions:
1. Create an appropriate /etc/tftpaccess.ctl file.
2. From the directory containing the new tftpd module, issue
the following commands as root.
# chmod 644 /etc/tftpaccess.ctl
# chown root.system /etc/tftpaccess.ctl
# mv /etc/tftpd /etc/tftpd.old
# cp tftpd /etc
# chmod 755 /etc/tftpd
# chown root.system /etc/tftpd
# refresh -s inetd
===========================================================================
/usr/ucb/rdist Vulnerability
---------------------------------------------------------------------------
Information concerning a vulnerability in /usr/ucb/rdist (the location of
rdist may vary depending on the operating system). This vulnerability is
present in possibly all versions of rdist. Vendors responding with patches
are listed below. Additionally, some vendors who do not include rdist in
their operating systems are identified. Operating systems from vendors not
listed in either of the two categories below will probably be affected and
the CERT/CC has proposed a workaround for those systems.
VENDORS THAT DO NOT SHIP rdist
(Note: Even though these vendors do not ship rdist, it may have been
added later (for example, by the system administrator). It is
also possible that vendors porting one of these operating systems
may have added rdist. In both cases corrective action must be taken.)
Amdahl
AT&T System V
Data General DG/UX for AViiON Systems
VENDORS PROVIDING PATCHES
Cray Research, Inc. UNICOS 6.0/6.E/6.1 Field Alert #132 SPR 47600
For further information contact the Support Center at 1-800-950-CRAY or
612-683-5600 or e-mail support@crayamid.cray.com.
NeXT Computer, Inc. NeXTstep Release 2.x
A new version of rdist may be obtained from your
authorized NeXT Support Center. If you are an authorized
support center, please contact NeXT through your normal
channels. NeXT also plans to make this new version of
rdist available on the public NeXT FTP archives.
Silicon Graphics IRIX 3.3.x/4.0 (fixed in 4.0.1)
Patches may be obtained via anonymous ftp from sgi.com in the
sgi/rdist directory.
Sun Microsystems, Inc. SunOS 4.0.3/4.1/4.1.1 Patch ID 100383-02
Patches may be obtained via anonymous ftp from ftp.uu.net or from local
Sun Answer Centers worldwide.
All trademarks are the property of their respective holders.
---------------------------------------------------------------------------
I. Description
A security vulnerability exists in /usr/ucb/rdist that
can be used to gain unauthorized privileges. Under some
circumstances /usr/ucb/rdist can be used to create setuid
root programs.
II. Impact
Any user logged into the system can gain root access.
III. Solution
A. If available, install the appropriate patch provided by
your operating system vendor.
B. If no patch is available, restrict the use of /usr/ucb/rdist
by changing the permissions on the file.
# chmod 711 /usr/ucb/rdist
