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CERT Advisory CA-2002-06 Vulnerabilities in Various Implementations of the
                         RADIUS Protocol

   Original release date: March 4, 2002
   Last revised: --
   Source: CERT/CC

   A complete revision history can be found at the end of this file.

Systems Affected

   Systems running any of the following RADIUS implementations:

     * Ascend RADIUS versions 1.16 and prior
     * Cistron RADIUS versions 1.6.5 and prior
     * FreeRADIUS versions 0.3 and prior
     * GnuRADIUS versions 0.95 and prior
     * ICRADIUS versions 0.18.1 and prior
     * Livingston RADIUS versions 2.1 and earlier
     * RADIUS (previously known as Lucent RADIUS) versions 2.1 and prior
     * RADIUSClient versions 0.3.1 and prior
     * XTRADIUS 1.1-pre1 and prior
     * YARD RADIUS 1.0.19 and prior

Overview

   Remote Authentication Dial In User Service (RADIUS) servers are used
   for authentication, authorization and accounting for terminals that
   speak the RADIUS protocol. Multiple vulnerabilities have been
   discovered in several implementations of the RADIUS protocol.

I. Description

   Two vulnerabilities in various implementations of RADIUS clients and
   servers have been reported to several vendors and the CERT/CC. They
   are remotely exploitable, and on most systems result in a denial of
   service. VU#589523 may allow the execution of code if the attacker has
   knowledge of the shared secret.

   VU#589523 - Multiple implementations of the RADIUS protocol contain a
   digest calculation buffer overflow

     Multiple implementations of the RADIUS protocol contain a buffer
     overflow in the function that calculates message digests.

     During the message digest calculation, a string containing the
     shared secret is concatenated with a packet received without
     checking the size of the target buffer. This makes it possible to
     overflow the buffer with shared secret data. This can lead to a
     denial of service against the server. If the shared secret is known
     by the attacker, then it may be possible to use this information to
     execute arbitrary code with the privileges of the victim RADIUS
     server or client, usually root. It should be noted that gaining
     knowledge of the shared secret is not a trivial task.

     Systems Affected by VU#589523

     * Ascend RADIUS versions 1.16 and prior
     * Cistron RADIUS versions 1.6.4 and prior
     * FreeRADIUS versions 0.3 and prior
     * GnuRADIUS versions 0.95 and prior
     * ICRADIUS versions 0.18.1 and prior
     * Livingston RADIUS versions 2.1 and earlier
     * RADIUS (commonly known as Lucent RADIUS) versions 2.1 and prior
     * RADIUSClient versions 0.3.1 and prior
     * YARD RADIUS 1.0.19 and prior
     * XTRADIUS 1.1-pre1 and prior

   VU#936683 - Multiple implementations of the RADIUS protocol do not
   adequately validate the vendor-length of vendor-specific attributes.

     Various RADIUS servers and clients permit the passing of
     vendor-specific and user-specific attributes. Several
     implementations of RADIUS fail to check the vendor-length of
     vendor-specific attributes. It is possible to cause a denial of
     service against RADIUS servers with a malformed vendor-specific
     attribute.

     RADIUS servers and clients fail to validate the vendor-length
     inside vendor-specific attributes. The vendor-length shouldn't be
     less than 2. If vendor-length is less than 2, the RADIUS server (or
     client) calculates the attribute length as a negative number. The
     attribute length is then used in various functions. In most RADIUS
     servers the function that performs this calculation is rad_recv()
     or radrecv(). Some applications may use the same logic to validate
     user-specific attributes and be vulnerable via the same method.

     Systems Affected by VU#936683

     * Cistron RADIUS versions 1.6.5 and prior
     * FreeRADIUS versions 0.3 and prior
     * ICRADIUS versions 0.18.1 and prior
     * Livingston RADIUS versions 2.1 and earlier
     * YARD RADIUS 1.0.19 and prior
     * XTRADIUS 1.1-pre1 and prior

II. Impact

   Both of the vulnerabilities allow an attacker can cause a denial of
   service of the RADIUS server. On some systems, VU#589523 may allow the
   execution of code if the attacker has knowledge of the shared secret.

III. Solution

   Apply a patch, or upgrade to the version specified by your vendor.
   Block packets to the RADIUS server at the firewall

   Limit access to the RADIUS server to those addresses which are
   approved to authenticate to the RADIUS server. Note that this does not
   protect your server from attacks originating from these addresses.

Appendix A. - Vendor Information

   This appendix contains information provided by vendors for this
   advisory. When vendors report new information to the CERT/CC, we
   update this section and note the changes in our revision history. If a
   particular vendor is not listed below, we have not received their
   comments.

 Apple

     Mac OS X and Mac OS X Server -- Not vulnerable since RADIUS is not
     shipped with those products.

 Cisco

     Cisco Systems has reviewed the following products that implement
     RADIUS with regards to this vulnerability, and has determined that
     the following are NOT vulnerable to this issue; Cisco IOS, Cisco
     Catalyst OS, Cisco Secure PIX firewall, Cisco Secure Access Control
     System for Windows, Cisco Aironet, Cisco Access Registrar, and
     Cisco Resource Pooling Management Service. At this time, we are not
     aware of any Cisco products that are vulnerable to the issues
     discussed in this report.

 Cistron

     You state 2 vulnerabilities:
    1. Digest Calculation Buffer Overflow Vulnerability Cistron Radius up
       to and including 1.6.4 is vulnerable
    2. Invalid attribute length calculation on malformed Vendor-Specific
       attr. Cistron Radius up to and including 1.6.5 is vulnerable

     Today I have released version 1.6.6, which also fixes (2). The
     homepage is http://www.radius.cistron.nl/ on which you can also
     find the ChangeLog. An announcement to the cistron-radius
     mailinglist was also made today.

     So everybody should upgrade to 1.6.6.

 FreeBSD

     FreeBSD versions prior to 4.5-RELEASE (which is shipping today or
     tomorrow or so) do contain some of the RADIUS packages mentioned
     below: radiusd-cistron, freeradius, ascend-radius, icradius, and
     radiusclient. However, 4.5-RELEASE will not ship with any of these
     RADIUS packages, except radiusclient. Also, note that the
     information you [CERT/CC] have forwarded previously indicates that
     neither Merit RADIUS (radius-basic) nor radiusclient are
     vulnerable.

 Fujitsu

     Fujitsu's UXP/V operating system is not vulnerable because UXP/V
     does not support the Radius functionality.

 GnuRADIUS

     The bug was fixed in version 0.96.

 Hewlett-Packard

     We have tested our Version of RADIUS, and we are NOT vulnerable.

 IBM

     IBM's AIX operating system, all versions, is not vulnerable as we
     do not ship the RADIUS project with AIX.

 Juniper Networks

     Juniper products have been tested and are not affected by this
     vulnerability.

 Lucent Technologies, Inc.

     Lucent and Ascend "Free" RADIUS server Product Status
     
     Reiteration of product End of Life
     February 14, 2002
     
     The purpose of this announcement is to make official the end of
     life of products based on the Livingston Enterprises RADIUS server,
     and to reiterate the terms of the original license.
     
     Prior to the Lucent Technologies acquisition of Ascend Communications
     and Livingston Enterprises, both companies distributed RADIUS servers
     at no cost to their customers. The initial Livingston server was
     RADIUS 1.16 followed in June 1999 by RADIUS 2.1. The Ascend server
     was based on the Livingston 1.16 product with the most recent version
     being released in June 1998. Lucent Technologies no longer
     distributes these products, does not provide any support services for
     these products, and has not done so for some time.
     
     All of these products were distributed as-is without warranty,
     under the BSD "Open Source" license with the following terms:
     
     This software is provided by the copyright holders and contributors
     ``as is'' and any express or implied warranties, including, but not
     limited to, the implied warranties of merchantability and fitness for
     a particular purpose are disclaimed. In no event shall the copyright
     holder or contributors be liable for any direct, indirect,
     incidental, special, exemplary, or consequential damages (including,
     but not limited to, procurement of substitute goods or services;
     loss of use, data, or profits; or business interruption) however
     caused and on any theory of liability, whether in contract, strict
     liability, or tort (including negligence or otherwise) arising in any
     way out of the use of this software, even if advised of the
     possibility of such damage.
     
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     
     * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
     
     * Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the
     distribution.
     
     * All advertising materials mentioning features or use of this
     software must display the following acknowledgement:
     This product includes software developed by Lucent Technologies and
     its contributors.
     
     * Neither the name of the copyright holder nor the names of its
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

     Under this license, other parties are free to develop and release
     other products and versions. However, as noted in the license terns,
     Lucent Technologies can not and does not assume any responsibility
     for any releases, present or future, based on these products.
     
     Replacement Product
     
     The replacement product is NavisRadius 4.x. NavisRadius is a fully
     supported commercial product currently available from Lucent
     Technologies. Please visit the NavisRadius product web site at
     http://www.lucentradius.com for product information and free
     evaluation copies.
     
     Richard Perlman
     NavisRadius Product Management
     Network Operations Software
     perllucent.com
     +1 510-747-5650
     

 Microsoft

     We've completed our investigation into this issue based on the
     information provided and have determined that no version of
     Microsoft IAS is susceptible to either vulnerability.

 NetBSD

     Some of the affected radius daemons are available from NetBSD
     pkgsrc. It is highly advisable that you update to the latest
     versions available from pkgsrc. Also note that
     pkgsrc/security/audit-packages can be used to notify you when new
     pkgsrc related security issues are announced.

 Process Software

     MultiNet and TCPware do not provide a RADIUS implementation.

 RADIUS (previously known as Lucent RADIUS)

     I wish to advise that Lucent Radius 2.1 is vulnerable to VU#589523,
     but is not vulnerable to VU#936683.

     I have made an unofficial patch to this code to resolve this
     problem. It will be released in ftp://ftp.vergenet.net/pub/radius/
     where previous patches to Radius by myself are available.

 RADIUSClient

     I've just uploaded version 0.3.2 of the radiusclient library to
     ftp://ftp.cityline.net/pub/radiusclient/radiusclient-0.3.2.tar.gz
     which contains a fix for the reported buffer overflow.

 Red Hat

     We do not ship any radius software as part of any of our main
     operating system. However, Cistron RADIUS was part of our
     PowerTools add-on software CD from versions 5.2 through 7.1. Thus
     while not installed by default, some users of Red Hat Linux may be
     using Cistron RADIUSD. Errata packages that fix this problem and
     our advisory will be available shortly on our web site at the URL
     below. At the same time users of the Red Hat Network will be able
     to update their systems to patched versions using the up2date tool.

     http://www.redhat.com/support/errata/RHSA-2002-030.html

 SCO

     The Caldera NON-Linux operating systems: OpenServer, UnixWare, and
     Open UNIX, do not ship Radius servers or clients.

 SGI

     SGI does not ship with a RADIUS server or client, so we are not
     vulnerable to these issues.

 Wind River Systems

     The current RADIUS client product from Wind River Systems, WindNet
     RADIUS 1.1, is not susceptible to VU#936683 and VU#589523 in our
     internal testing.

     VU#936683 - WindNet RADIUS will pass the packet up to the
     application. The application may need to be aware of the invalid
     attribute length.

     VU#589523 - WindNet RADIUS will drop the packet overflow.

     Please contact Wind River support at supportwindriver.com or call
     (800) 458-7767 with any test reports related to VU#936683 and
     VU#589523.

 XTRADIUS

     We are trying to relase a new and fixed version of xtradius by the
     end of the month (version 1.2.1).. Right now the new version is on
     the CVS and we are testing it...

 YARD RADIUS

     Current version 1.0.19 of Yardradius (which is derived from Lucent
     2.1) seems suffering both the problems. I think I will release a
     new version (1.0.20) which solves those buffer overflows before
     your suggested date [3/4/2002].
   _________________________________________________________________

   Our thanks to 3APA3A <3APA3Asecurity.nnov.ru> and Joshua Hill and for
   their cooperation, reporting and analysis of this vulnerability.
   _________________________________________________________________

   Feedback about this Advisory can be sent to the author,
   Jason A. Rafail.
   _________________________________________________________________

Appendix B. - References

    1. http://www.kb.cert.org/vuls/id/589523
    2. http://www.kb.cert.org/vuls/id/936683
    3. http://www.security.nnov.ru/advisories/radius.asp
    4. http://www.untruth.org/~josh/security/radius
    5. http://www.securityfocus.com/bid/3530
   ______________________________________________________________________

   This document is available from:
   http://www.cert.org/advisories/CA-2002-06.html
   ______________________________________________________________________

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   Revision History
March 04, 2002: Initial release

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