-----BEGIN PGP SIGNED MESSAGE-----
__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Capability
___ __ __ _ ___
/ | /_\ /
\___ __|__ / \ \___
__________________________________________________________
INFORMATION BULLETIN
Vulnerability in rlogin/term
October 28, 1997 23:00 GMT Number H-25a
______________________________________________________________________________
PROBLEM: A vulnerability in many implementations of the rlogin program,
including eklogin and klogin.
PLATFORM: Systems using any of the listed vendors maybe vulnerable.
Berkeley Software Design, Inc. (BSDI)
Cray Research - A Silicon Graphics Company
Digital Equipment Corporation
FreeBSD, Inc.
Hewlett-Packard Corporation
IBM Corporation
Linux Systems
NEC Corporation
NeXT Software, Inc.
The Open Group
The Santa Cruz Operation (SCO)
Sun Microsystems, Inc.
DAMAGE: Local users may gain root privileges.
SOLUTION: Install vendor patches for this problem as listed in (Sec.
III.A). Until you can do so, turn off rlogin or replace it with
a wrapper (see Sec. III.B.2).
______________________________________________________________________________
VULNERABILITY Exploit details involving this vulnerability have been made
ASSESSMENT: publicly available.
______________________________________________________________________________
[ Appended to H-25 on October 28, 1997 with patch release information from Sun ]
[ Start CERT Advisory ]
=============================================================================
CERT(sm) Advisory CA-97.06
Original issue date: February 6, 1997
Last revised: --
Topic: Vulnerability in rlogin/term
- ------------------------------------------------------------------------------
The CERT Coordination Center has received reports of a vulnerability in many
implementations of the rlogin program, including eklogin and klogin. By
exploiting this vulnerability, users with access to an account on the system
can cause a buffer overflow and execute arbitrary programs as root.
The CERT/CC staff recommends installing a vendor patch for this problem
(Sec. III.A). Until you can do so, we urge you to turn off rlogin or replace
it with a wrapper (see Sec. III.B.2).
We will update this advisory as we receive additional information.
Please check advisory files regularly for updates that relate to your site.
- ------------------------------------------------------------------------------
I. Description
The rlogin program provided by many UNIX systems, as well as some non-UNIX
systems, is described in RFC 1282. Here is an excerpt from that RFC that
describes its elemental functionality:
"The rlogin facility provides a remote-echoed, locally flow-
controlled virtual terminal with proper flushing of output.
It is widely used between Unix hosts because it provides
transport of more of the Unix terminal environment semantics
than does the Telnet protocol, and because on many Unix hosts
it can be configured not to require user entry of passwords
when connections originate from trusted hosts."
The key point from this description is that the rlogin program passes
the terminal type description from the local host to the remote host.
This functionality allows terminal-aware programs such as full-screen
text editors to operate properly across a computer-to-computer
connection created with rlogin.
To do this, the rlogin program uses the current terminal definition as
identified by the TERM environment variable. The protocol described in
RFC 1282 explains how this terminal information is transferred from the
local machine where the rlogin client program is running to the remote
machine where service is sought.
Unfortunately, many implementations of the rlogin program contain a
defect whereby the value of the TERM environment variable is copied to
an internal buffer without due care. The buffer holding the copied value
of TERM can be overflowed. In some implementations, the buffer is a local
variable, meaning that the subroutine call stack can be overwritten and
arbitrary code executed. The executed code is under the control of the
user running the rlogin program.
In addition, the rlogin program is set-user-id root. rlogin requires
these increased privileges so it can allocate a port in the required
range, as described in the in.rlogind (or rlogind) manual page:
"The server checks the client's source port. If the port is not
in the range 0-1023, the server aborts the connection."
In summary, rlogin is a set-user-id root program that in many
implementations contains a programming defect whereby an internal buffer
can be overflowed and arbitrary code can be executed as root.
II. Impact
Users can become root if they have access to an account on the system.
III. Solution
Install a patch from your vendor if one is available (Section A).
Until you can take one of those actions, we recommend applying the
workaround described in Section B.
A. Obtain and install a patch for this problem.
Below is a list of vendors who have provided information about
rlogin. Details are in Appendix A of this advisory; we will update
the appendix as we receive more information. If your vendor's name is
not on this list, the CERT/CC did not hear from that vendor. Please
contact your vendor directly.
Berkeley Software Design, Inc. (BSDI)
Cray Research - A Silicon Graphics Company
Digital Equipment Corporation
FreeBSD, Inc.
Hewlett-Packard Corporation
IBM Corporation
Linux Systems
NEC Corporation
NeXT Software, Inc.
The Open Group
The Santa Cruz Operation (SCO)
B. Until you are able to install the appropriate patch, we recommend
one of the following workarounds:
1. Turn off rlogin.
If your user community does not use rlogin, turn it off.
As root, do the following:
% chmod 0 /usr/bin/rlogin
You may find the rlogin program in some other directory on
your system. Example directories are: /bin, /usr/bin, /usr/ucb.
Note: On some systems, rlogin is provided in different forms
that do additional work. Examples are eklogin (kerberos
authentication plus encryption of the data stream) and klogin
(kerberos authentication only). These, too, need to be turned
off.
2. Replace the rlogin program with a wrapper.
We have written a prototype wrapper that is available at
URL ftp://info.cert.org/pub/tools/rlogin_wrapper/rlogin_wrapper.c
The PGP signature for this file is available at
URL ftp://info.cert.org/pub/tools/rlogin_wrapper/rlogin_wrapper.c.asc
To verify that this file is correct, fetch both the
rlogin_wrapper.c and rlogin_wrapper.c.asc files and check the
signature with pgp as in
% pgp rlogin_wrapper.c.asc rlogin_wrapper.c
Notes:
* You may have to change this program to get it to compile and
work correctly on your system.
* If you have different forms of rlogin, as noted in the
previous section, then you will need to replace those forms
with the wrapper as well.
- ------------------------------------------------------------------------------
Appendix A - Vendor Information
Below is a list of the vendors who have provided information for this
advisory. We will update this appendix as we receive additional information.
If you do not see your vendor's name, the CERT/CC did not hear from that
vendor. Please contact the vendor directly.
Berkeley Software Design, Inc. (BSDI)
====================================
Unpatched BSD/OS 2.1 systems are vulnerable to this problem. A patch
was issued that resolved this problem in August 1996. The patch is
available from the <patches@BSDI.COM> mail server or via anonymous ftp
at:
ftp://ftp.bsdi.com/bsdi/patches/patches-2.1/U210-021
Cray Research - A Silicon Graphics Company
==========================================
This problem has been corrected in all currently supported versions
of Unicos.
Digital Equipment Corporation
=============================
At the time of writing this document, patches(binary kits) are
available from your normal Digital Support Channel.
rlogin patches are available for:
DIGITAL UNIX V3.2c, V3.2de1/de2, V3.2g, V3.2g, V4.0, V4.0a, V4.0b.
DIGITAL ULTRIX V4.4 VAX & MIPS, V4.5 VAX and MIPS
DIGITAL EQUIPMENT CORPORATION
-----------------------------
FreeBSD, Inc.
=============
This vulnerability is present in FreeBSD 2.1.5 and previous
versions. It was fixed in all FreeBSD source and
binary distributions dated after 1996/07/25.
The following source code patch may be applied to FreeBSD
2.1.5 based distributions, and should work in previous
distributions. Users unable to apply this patch and
recompile the rlogin binary are encouraged to use the
wrapper provided by CERT.
Index: rlogin.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/rlogin/rlogin.c,v
retrieving revision 1.5.4.1
retrieving revision 1.5.4.2
diff -c -r1.5.4.1 -r1.5.4.2
*** rlogin.c 1996/06/23 13:08:27 1.5.4.1
- - --- rlogin.c 1996/07/25 18:29:35 1.5.4.2
***************
*** 102,107 ****
- - --- 102,108 ----
char *speeds[] = {
"0", "50", "75", "110", "134", "150", "200", "300", "600", "1200",
"1800", "2400", "4800", "9600", "19200", "38400", "57600", "115200"
+ #define MAX_SPEED_LENGTH (sizeof("115200") - 1)
};
#ifdef OLDSUN
***************
*** 259,265 ****
exit(1);
}
! (void)strcpy(term, (p = getenv("TERM")) ? p : "network");
if (ioctl(0, TIOCGETP, &ttyb) == 0) {
(void)strcat(term, "/");
(void)strcat(term, speeds[(int)ttyb.sg_ospeed]);
- - --- 260,270 ----
exit(1);
}
! #define MAX_TERM_LENGTH (sizeof(term) - 1 - MAX_SPEED_LENGTH - 1)
!
! (void)strncpy(term, (p = getenv("TERM")) ? p : "network",
! MAX_TERM_LENGTH);
! term[MAX_TERM_LENGTH] = '\0';
if (ioctl(0, TIOCGETP, &ttyb) == 0) {
(void)strcat(term, "/");
(void)strcat(term, speeds[(int)ttyb.sg_ospeed]);
Hewlett-Packard Corporation
===========================
This rlogin problem is fixed:
PHNE_8807 10.20 s700/800
PHNE_8806 10.10, 10.0X s700/800
PHNE_8805 9.X s700/800
See Hewlett-Packard Security Bulletin HPSBUX9702-052, dated
February 5, 1997.
IBM Corporation
===============
See the appropriate release below to determine your action.
AIX 3.2
-------
Apply the following fix to your system:
APAR - IX57724 (PTF - U442613)
To determine if you have this PTF on your system, run the following
command:
lslpp -lB U442613
AIX 4.1
-------
Apply the following fix to your system:
APAR - IX57972
To determine if you have this APAR on your system, run the following
command:
instfix -ik IX57972
Or run the following command:
lslpp -h bos.net.tcp.client
Your version of bos.net.tcp.client should be 4.1.4.13 or later.
AIX 4.2
-------
No APAR required. Fix already contained in the release.
To Order
--------
APARs may be ordered using Electronic Fix Distribution (via FixDist)
or from the IBM Support Center. For more information on FixDist,
reference URL:
http://service.software.ibm.com/aixsupport/
or send e-mail to aixserv@austin.ibm.com with a subject of "FixDist".
IBM and AIX are registered trademarks of International Business Machines
Corporation.
Linux Systems
=============
Only very out of date Linux systems are vulnerable.
Linux Netkit 0.08 has rlogin fixed. All Linux systems using older
NetKits should upgrade to NetKit 0.09. Some vendors have shipped
patched Netkit-0.08 releases. Check with your vendor for
confirmation.
NetKit 0.09 is available from:
ftp://ftp.uk.linux.org/pub/linux/Networking/base/NetKit-0.09.tar.gz
NEC Corporation
===============
UX/4800 Not vulnerable for all versions.
EWS-UX/V(Rel4.2MP) Not vulnerable for all versions.
EWS-UX/V(Rel4.2) Not vulnerable for all versions.
UP-UX/V(Rel4.2MP) Not vulnerable for all versions.
NeXT Software, Inc.
===================
This problem is fixed in OpenStep/Mach release 4.1 and later.
The Open Group
==============
This problem was fixed in OSF's OSF/1 R1.3.3 maintenance release.
The Santa Cruz Operation (SCO)
==============================
SCO is investigating this problem and should a patch be necessary, SCO
will provide updated information for this advisory. Patches for SCO
products are listed at ftp://ftp.sco.COM/SLS/README.
- ------------------------------------------------------------------------------
[ End CERT Advisory ]
[ Start Sun Bulletin ]
______________________________________________________________________________
Sun Microsystems, Inc. Security Bulletin
Bulletin Number: #00158
Date: October 28, 1997
Cross-Ref: CERT CA-97.06
Title: rlogin
______________________________________________________________________________
Permission is granted for the redistribution of this Bulletin, so long as
the Bulletin is not edited and is attributed to Sun Microsystems. Portions
may also be excerpted for re-use in other security advisories so long as
proper attribution is included.
Any other use of this information without the express written consent of
Sun Microsystems is prohibited. Sun Microsystems expressly disclaims all
liability for any misuse of this information by any third party.
______________________________________________________________________________
1. Bulletins Topics
Sun announces the release of patches for Solaris 2.5.1, 2.5, 2.4, 2.3,
(SunOS 5.5.1, 5.5, 5.4, 5.3), SunOS 4.1.4 and 4.1.3_U1 which relate to a
vulnerability in rlogin.
Sun strongly recommends that you install the patches listed in section 4
immediately on systems running SunOS 5.5.1, 5.5, 5.4, 5.3, 4.1.4, and
4.1.3_U1.
2. Who is Affected
Vulnerable: SunOS versions 5.5.1, 5.5.1_x86, 5.5, 5.5_x86,
5.4, 5.4_x86, 5.3, 4.1.4, 4.1.3_U1
The vulnerability is fixed in Solaris 2.6.
3. Understanding the Vulnerability
The rlogin program establishes a remote login session. Due to insufficient
bounds checking on arguments supplied to rlogin, it is possible to
overwrite the internal data space of the rlogin program. As rlogin is
setuid root, this vulnerability may be exploited to gain root access.
4. List of Patches
The vulnerability in rlogin is fixed by the following patches:
OS version Patch ID
__________ ________
SunOS 5.5.1 104650-02
SunOS 5.5.1_x86 104651-02
SunOS 5.5 104669-02
SunOS 5.5_x86 104670-02
SunOS 5.4 105254-01
SunOS 5.4_x86 105255-01
SunOS 5.3 105253-01
SunOS 4.1.4 105260-01
SunOS 4.1.3_U1 105259-01
5. Checksum Table
The checksum table below shows the BSD checksums (SunOS 4.1.x: /bin/sum;
SunOS 5.x: /usr/ucb/sum), SVR4 checksums (SunOS 4.1.x: /usr/5bin/sum;
SunOS 5.x: /usr/bin/sum), and the MD5 digital signatures for the
above-mentioned patches that are available from:
<URL:ftp://sunsolve1.sun.com/pub/patches/patches.html>
These checksums may not apply if you obtain patches from your answer
centers.
File Name BSD SVR4 MD5
_______________ _________ __________ ________________________________
104650-02.tar.Z 13535 97 28313 194 09633D56EE7957B583EA7B56868C041A
104651-02.tar.Z 63944 97 59194 194 62FC76D27F05D9088734AFB2FBA728B4
104669-02.tar.Z 50300 97 53035 194 603DBCACC7E43DB308F6191BC9FA5D69
104670-02.tar.Z 53991 97 53938 193 2AAB302E10CF860B4009E1CF873B1AE7
105254-01.tar.Z 16467 86 40933 172 6C1C5E4A63C07B69E79CFE31308703F0
105255-01.tar.Z 61095 86 58884 172 CE00AF98291E033BEE5E49C049AD6162
105253-01.tar.Z 12622 86 40936 172 382904D4F14E247D17F9E59F1424480D
105260-01.tar.Z 06896 11 12684 22 191C9F074855631D4CCCD136FA267DEE
105259-01.tar.Z 18628 11 19352 22 CCC5434C6F71AE02C5B456CE4C8BDBBE
______________________________________________________________________________
APPENDICES
A. Patches listed in this bulletin are available to all Sun customers via
World Wide Web at:
<URL:ftp://sunsolve1.sun.com/pub/patches/patches.html>
Customers with Sun support contracts can also obtain patches from local
Sun answer centers and SunSITEs worldwide.
B. Sun security bulletins are available via World Wide Web at:
<URL:http://sunsolve1.sun.com/sunsolve/secbulletins>
C. Sun Security Coordination Team's PGP key is available via World Wide Web
at:
<URL:http://sunsolve1.sun.com/sunsolve/secbulletins/SunSCkey.txt>
D. To report or inquire about a security problem with Sun software, contact
one or more of the following:
- Your local Sun answer centers
- Your representative computer security response team, such as CERT
- Sun Security Coordination Team. Send email to:
security-alert@sun.com
E. To receive information or subscribe to our CWS (Customer Warning System)
mailing list, send email to:
security-alert@sun.com
with a subject line (not body) containing one of the following commands:
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Note that your-email-address should be substituted
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______________________________________________________________________________
[ End Sun Bulletin ]
______________________________________________________________________________
CIAC wishes to acknowledge the contributions of CERT, AUSCERT, DFN-CERT and
Sun Microsystems, Inc. for the information contained in this bulletin.
______________________________________________________________________________
CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
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