************************************************************************** Security Bulletin 9552 DISA Defense Communications System December 14, 1995 Published by: DISN Security Coordination Center (SCC@NIC.DDN.MIL) 1-(800) 365-3642 DEFENSE INFORMATION SYSTEM NETWORK SECURITY BULLETIN The DISN SECURITY BULLETIN is distributed by the DISN SCC (Security Coordination Center) under DISA contract as a means of communicating information on network and host security exposures, fixes, and concerns to security and management personnel at DISN facilities. Back issues may be obtained via FTP (or Kermit) from NIC.DDN.MIL [192.112.36.5] using login="anonymous" and password="guest". The bulletin pathname is scc/sec-yynn (where "yy" is the year the bulletin is issued and "nn" is a bulletin number, e.g. scc/sec-9544.txt). These are also available at our WWW site, http://nic.ddn.mil. ************************************************************************** + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + ! ! ! The following important advisory was issued by the Automated ! ! Systems Security Incident Support Team (ASSIST) and is being ! ! relayed unedited via the Defense Information Systems Agency's ! ! Security Coordination Center distribution system as a means ! ! of providing DISN subscribers with useful security information. ! ! ! + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + -----BEGIN PGP SIGNED MESSAGE----- <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Automated Systems Security Incident Support Team _____ ___ ___ _____ ___ _____ | / /\ / \ / \ | / \ | | / Integritas / \ \___ \___ | \___ | | < et /____\ \ \ | \ | | \ Celeritas / \ \___/ \___/ __|__ \___/ | |_____\ <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bulletin 95-49 Release date: 13 December, 1995, 2:45 PM EST (GMT -5) SUBJECT: rpc.ypupdated Vulnerability. SUMMARY: A vulnerability exists in the rpc.ypupdated program. A program that exploits this problem has been publicized and distributed on the Internet. BACKGROUND: The rpc.ypupdated program is a server used to change NIS information from a network-based client using various methods of authentication. Clients connect to rpc.ypupdated and provide authentication information and proposed changes to an NIS database. If authenticated, the information provided is used to update the selected NIS database. The protocol used when clients communicate with a server only checks to see if the connection is authentic using secure RPC. The protocol does not check to see if the client is authorized to modify the NIS data or if the given NIS map exists. Even after an unsuccessful attempt to update the NIS information, the rpc.ypupdated server invokes the make(1) program to propagate possible changes. The invocation of make is implemented in an insecure fashion, which allows the requesting client to pass malicious arguments and execute arbitrary commands on the NIS master and slave servers. IMPACT: Allows remote users to execute arbitrary programs on machines that provide Network Information Service (NIS) master and slave services. Client machines of an NIS master or slave server are not affected. RECOMMENDED SOLUTIONS: First, determine if systems are vulnerable using the information in section "A" below. If vulnerable, follow the instructions vendors have provided in the appendix or apply the workaround in section "B" below. A. Consult the vendor information in the appendix. If your vendor is not listed, then check to see if your system has an rpc.ypupdated server. To do this check, consult your system documentation or look in your system initialization files (e.g., /etc/rc*, /etc/init.d/*, and inetd.conf) for rpc.ypupdated or ypupdated. If you find a reference to this program on your system, the probability is high that your system is vulnerable. B. On vulnerable systems, ASSIST recommends rpc.ypupdated be disabled until a ptach is available. Some examples for disabling rpc.ypupdated are listed below, consult your system documentation for additional information about how to accomplish this task on your system. In these examples, the rpc.ypupdated program is terminated if it is running, and the system is reconfigured to prevent the daemon from automatically starting when the system is rebooted. Example 1 - SunOS 4.1.X For SunOS 4.1.X master and slave NIS servers, the rpc.ypupdated program is started by the /etc/rc.local script. First, determine if the server is running, and kill it. Second, rename rpc.ypupdated so that the /etc/rc.local script will not find and start it when the system reboots. # /bin/uname -a SunOS test-sun 4.1.4 1 sun4m # /bin/ps axc | /bin/grep rpc.ypupdated 108 ? IW 0:00 rpc.ypupdated # /bin/kill 108 # /bin/ps axc | /bin/grep rpc.ypupdated # /bin/grep ypupdated /etc/rc /etc/rc.local /etc/rc.local: if [ -f /usr/etc/rpc.ypupdated -a -d /var/yp/$dname ]; then /etc/rc.local: rpc.ypupdated; echo -n ' ypupdated' # /bin/mv /usr/etc/rpc.ypupdated /usr/etc/rpc.ypupdated.CA-95:17 # /bin/chmod 0 /usr/etc/rpc.ypupdated.CA-95:17 Example 2 - IRIX On IRIX systems, ypupdated is started by the inetd daemon. For versions 3.X, 4.X, 5.0.X, 5.1.X, and 5.2, the ypupdated is enabled; but for versions 5.3, 6.0.X, and 6.1, it is disabled. Note that the byte counts given for /bin/ed may vary from system to system. Note also that the inetd.conf file is found in different locations for different releases of IRIX. For 3.X and 4.X, it is located in /usr/etc/inetd.conf. For all other releases (5.0.X, 5.1.X, 5.2, 5.3, 6.0.X, and 6.1) it is in /etc/inetd.conf. # /bin/uname -a IRIX test-iris 5.2 02282015 IP20 mips # /bin/grep ypupdated /etc/inetd.conf ypupdated/1 stream rpc/tcp wait root /usr/etc/rpc.ypupdated ypupdated # /bin/ps -eaf | /bin/grep rpc.ypupdated root 184 1 0 Nov 20 ? 0:00 /usr/etc/rpc.ypupdated root 14694 14610 2 11:30:07 pts/3 0:00 grep -i rpc.ypupdated # /bin/kill 184 # /bin/ed /etc/inetd.conf 3344 /^ypupdated/s/^/#DISABLED# /p #DISABLED# ypupdated/1 stream rpc/tcp wait root /usr/etc/rpc.ypupdated ypupdated w 3355 q # /bin/ps -eac | /bin/grep inetd 193 TS 26 ? 0:04 inetd # /bin/kill -HUP 193 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST would like to thank the CERT Coordination Center for information contained in this bulletin. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST is an element of the Defense Information Systems Agency (DISA), and provides service to the entire DoD community. Constituents of the DoD with questions about ASSIST or computer security issues, can contact ASSIST using one of the methods listed below. Non-DoD organizations/institutions, contact the Forum of Incident Response and Security Teams (FIRST) representative. To obtain a list of FIRST member organizations and their constituencies send an email to docserver@first.org with an empty "subject" line and a message body containing the line "send first-contacts". ASSIST Information Resources: To be included in the distribution list for the ASSIST bulletins, send your Milnet (Internet) e-mail address to assist-request@assist.mil. Back issues of ASSIST bulletins, and other security related information, are available from the ASSIST BBS at 703-607-4710, 327-4710, and through anonymous FTP from assist.mil (IP address 199.211.123.11). Note: assist.mil will only accept anonymous FTP connections from Milnet addresses that are registered with the NIC or DNS. If your system is not registered, you must provide your MILNET IP address to ASSIST before access can be provided. ASSIST Contact Information: PHONE: 800-357-4231, COMM 703-607-4700, DSN 327-4700. ELECTRONIC MAIL: assist@assist.mil. ASSIST BBS: COMM 703-607-4710, DSN 327-4710, leave a message for the "sysop". FAX: COMM 703-607-4735, DSN 607-4735 ASSIST uses Pretty Good Privacy (PGP) 2.6.2 as the digital signature mechanism for bulletins. PGP 2.6.2 incorporates the RSAREF(tm) Cryptographic Toolkit under license from RSA Data Security, Inc. A copy of that license is available via anonymous FTP from net-dist.mit.edu (IP 18.72.0.3) in the file /pub/PGP/rsalicen.txt, and through the world wide web from http://net-dist.mit.edu/pgp.html. In accordance with the terms of that license, PGP 2.6.2 may be used for non-commercial purposes only. Instructions for downloading the PGP 2.6.2 software can also be obtained from net-dist.mit.edu in the pub/PGP/README file. PGP 2.6.2 and RSAREF may be subject to the export control laws of the United States of America as implemented by the United States Department of State Office of Defense Trade Controls. The PGP signature information will be attached to the end of ASSIST bulletins. Reference herein to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by ASSIST. The views and opinions of authors expressed herein shall not be used for advertising or product endorsement purposes. - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6 mQCNAi4uZ40AAAEEAM1uraimCNeh5PtzX7KoGxC2u8uMTdl8V5sujk3MHbWvCuOM W0FqDy5s9iwfQLZWzJ7cbM6L0mNOj8eJGoz7TqGKZDDRFlKAwg0x8joleZLC2gXw FVdF/g6Mdv7ok7heoa+Y//YMeADnsSrmzqLCnhFbKYffww3EbdH6sbnW3Io9AAUR tB9BU1NJU1QgVGVhbSA8YXNzaXN0QGFzc2lzdC5taWw+iQCVAwUQMJVF1JtBJ/Qs yeedAQFnqgQAp1rw7ONT41Mr3gHGs2aVpEwgOH6SeJ9sHZxUp4dJu+ogRMFrqdC+ +NBfzitzj9m1udFVDHpwsGawbv6wg43DDAKaTgIETCHYXa/OM5/9FCS3xJwC99Gb V1iOm8S/Q9FcJruKID9DG2WUJp2yPj+CjTuBQeLjGkqGjuSOR1TNXQiJAJUDBRAw lUPuYKf6jFkmJQkBAWg5A/9ykgo2ULWUsSzZjRkO9yPZUPAlpfH7ReaHwkapK69F fBzqwwQ8Gig1mL+qgmOHS8Zv+OAT491sWWsECN+dfpopFdsgS4Sec19ZjcMyhL1c BVIS9Cmbjetb6Kvfc39AMr0MRCrUlOkUd4qScjHysHFYRAwCl3STRjprNnUPKQbn f4kAlQMFEDB482bk8movIjSrbQEB/VgD/iap/CAb1jq8wMA3QleU8d6/QUqoPzgp jRhP0wP7K2GLVUV0d5sP4EptmzejqViZvlzt6ufnI1bML0Yt2U5loAeblnh714RX JcOmyAah6niiJSKuhCsYUzW6f3EBzXBn5tcu3GP35h+1VQunCQCMICCfnZ0r8Wcv EdwE9LxPYdueiQCVAwUQMHOjMwJPhGsUbeKNAQGOagQAgT5p6CwrIPpi+12yJ170 ekc3MPp8z0aNbvdCQWXTK6qtq1LmS65VeH0RE5xRponsgbWp+5JBvD22v0eGuSg7 7bnHT1HPXazPERAp8sw1zTERs7drMQE+JhHYylh3orKzHNf5EjFx10vwEXdfvGSc sP3Vpcx2xu0lUYHp5oHtPFiJAJUDBRAwar4DFKHh5Qavqe0BAeQqA/4xd0tdq9yF eUYrd1+ZriayzfSjCcIUlCDH1i7vXw1kiHkg2YpOoZLD9k+zNkbOyBs/r570fGHu A23SvUcUfaBUijT1jf9YGU5MQMdpx3p5qqI4kJ0GWUNySZNtaFy0qWNH8Z8NsNp3 FWllVeisye0qe96aoizW0dAyUymlM6YYn4kAlQMFEDBqqvga2zTcAviMgQEBN8wE AIu7O/Of4c1OvMc5tti4+gcyCVw41+fLjxQFB5EtkoW8Js6XhCsv3GcmzgCZw3g8 Sux7wxGe+lspZNV9rvv+JkDBWkA9O5HyOdmdv5JZM1UH41NettZM9Yw7kUtO7lAT aOb4ybHlqrBwJ8/+Lig7r7PwTL847JyGa3g229pGG/uEiQCVAwUQMGpTK+glSuMP TJd1AQE8KQP8Cu+FYuagNoBRllMIQryT9+0ngLRxJJTcTgIbLX4OPwa27JuXCukG kUIXRWFCqkRqkM/7ImZXeuUL4PmAX07f9ygGH7BUyqefhIWkxWFDaGHJVlg3l/pS Wh7NnC+nU6DUJNSzfwYStCABNptOcMiYaT1fY0+DkWpIgJVRTptquOWJAJUCBRAw aHX+IlGW2WZtAFEBATkXA/40QTxVP/x3aJDgC11cvFhwT7M+qJvhGSTRJOtrFz8i soZzihMeaQ8zLiu73dDlFz2E4f0+ettxsDcgFJADNmZ5H7WkPlf9gBUBne4KP2Y6 yIjOCMwd6T7HGm/ErF88DIJ2wn8irhzVRnBBWhnmQfSzr5a7mkjlA6GzAlFucGp3 eokAlQMFEDBpzIC58yc3bMt0GQEBgd4EAI0mE/5wXSWuBNApkALLjPAchBdeC4Kl YF4hQkfY/4YddeIasgTmINKOc5gJWgTHxPI2xKxjTAQhIZlOxuDyXWnBuK+x2hr4 iCh5unEIH+qaqdipGwWjFq0IZEmOOJaBRxlVt2hrmY6nRMpekitFLw8dhWHgI968 WVhJpWfBg+MhiQCVAwUQMGnMcmJl+kgHVnRVAQF+nQP/XK4xmIx1SmjoN9D+vNRY PSiKz8KEzh1Y2/5QTYA7iES8QXC4i/8HOWK7lyoL6FmWGxKYpU8isQ+DJpk0A4N0 U04JexpyFa0EeM/wsfp0YvAWesSVhV5UkDQU6hSC0U8rS1j/qtnSLZ4wXpapPSBh 82daDlxAQCVMzDoQYQZkMi+JAJUDBRAwacftBCZ9eY4KSdEBAbKGA/0VHArALL6v d0a0x7sn4o60Bk2fFzuaCBNTNzb11OOtuu47KMOZLwrl2jv+32ysIVEOXx+puhXP nQAgRrH0LGKV5FOY3B98AHuV+woOmfVjM2T3xB4Bs52Dz+HIIIhaWzzy3955tlp/ 6UyvZnD0QFLS/bre/Pog1Lgl0pxonmILhYkAlQIFEDBpJpXAx/wW8A8EIQEBPVoD /jwgG+7ZrWrb8/dqe6IZhSk8rq0JIHhSA2Hz1T7PhRvyDiquBJ3ulTeaX3BvuWqF bMuLJ4CTqXw9dexDehEnhGlxYycSXVzy8a34pLnmldii8oNvI1bLWMgd4HdM/PPZ GOgHmSIGrXMChkbddt9AoszDI0Whlbe9+wn6AeZVrJVaiQCVAgUQMGkkL2yh0IcG ee2RAQHrTgQAvBRce0S9yBvI/ufC/1jhE3LuUoA3YDdA8+UQ+UekaslZzOEgPs4K Za/nM9Y2vaRYscyzyIg8FGTzCdJQ2be9HZjSkB2xQuakeq88tlV32/cLcQSC8Zrw xsnPWujbIcWYg7B0hv8cCovef/w4kC9GyhjhIzPIsQ/Cr7/TYzheK12JAJUDBRAw Z/38o2xF3nu86kkBARanA/0XO4HBo6pT2xNCdQ7AW9UrvmTCiYUb0XVY7qCnkaPp Sn1KjsK2nGueDMGUBzvx9zWZ0xHAS+BSNkoM61gb9455KcbDwRqw6+47O/WuX1w9 fh7egjTY0kqN6YsP/vtirOuP+Krh19w/s6cDxbEBNbJIiZofRDFRRsZcZ8E2mLCP UIkAlQMFEDBn/EY7f8e8znZrHwEBxQwD/jP+CiwO3Nk45M5Ei++TZzdp7ak82hum XxVXplV2G4w8DN86pfl3IV/XvU67FQXg4NKJr+wm3JknDtlKZTE5g+aKkOYK6Fqt w3FjTd6PTDz11YRruCsdvBeYwMcHPe5XzIhgkwkMXX2Mp99q9LGKfV3087do2LNr V/2S/atn6IuqiQCVAwUQMGW6OliXq3zaXLJBAQFLwgP/bQ1C/Ph54RlRqw9rovJo SXp5wvQAfVqqnkL5nIIIK2uGputcmhMP8RqYKuRv4xaezkCDTeIE/P0327Ajc4// ca4SZCojxfqtrhw3EkfZtvFLJh1tsvAkqZkgHmjJxwA+lY78lQ1ncBZ99dePpuHu MBQew3769SkEA8kk/s5XiYqJAJUDBRAvXHHu0fqxudbcij0BAQFjA/0W8glucqO0 wtSPyCF3qGimFLHxZmd9Cw6Zlf8Ftfy8rPVrkGQGfioA29b64oZ1SUTwsswSbU8P n0KKFxvc6hYM5TzMg4gSu+vLh6pr4vMRdXyecF16z4BrUwIwZLP4rc5o/vyVDskI ahj1NdNYh6V8B0FUEbhVBxJBGfy2NF0bZ7QoQVNTSVNUIFRlYW0gPGFzc2lzdEBh c3Npc3QuaW1zLmRpc2EubWlsPokAlQIFEC45Ys3KbyuD/AwC1QEBKPED/2dwnN+/ OE2iHhvGwv3jZtsm6cH+GVkpNpc0w0vQOKvVwUnLwuETSv+eryz9Fl7nL0U2tv/5 V81dXqqc5C7EvOQW1Dt9RBSjEOundYrOzsfELIMrwh1iJXsIxG7g7iil0HeKzxsQ E/nBFwJbgP6SQaYF4wy7TPuXw+IVVddp0p1riQCVAgUQLi5x6IdGPdIwvm+pAQFN EwP+Ml0i+yurXH1ZvQApz+HKwqLrRTNsNdHu2CsQ/OdGo4Vq4eqyPTvrI1OVjm6o jye7GR3RMPygEcz0oox/+YfB5cmGugpZLFsWLspswrFGGCXLXY3Bq7mpH14GENU5 JMlHzazeRvdDbkSv700Xu25JshjWIzfTY2nNUNfFlRefQoY= =8gi/ - -----END PGP PUBLIC KEY BLOCK----- Appendix: Vendor Information Current as of December 12, 1995 If you do not see your vendor's name below, please contact ASSIST or the vendor directly for information. Apple Computer, Inc. - ------------------- A/UX does not include this functionality and is therefore not vulnerable. Berkeley Software Design, Inc. (BSDI) - ------------------------------------- BSD/OS by Berkeley Software Design, Inc. (BSDI) is not vulnerable. Data General Corporation - ------------------------ Data General believes the DG/UX operating system to be NOT vulnerable. This includes all supported release, DG/UX 5.4 Release 3.10, DG/UX Release 4.10 and all related Trusted DG/UX releases. Digital Equipment Corporation - ----------------------------- OSF/1 on all Digital platforms is not vulnerable. Analysis of ULTRIX is under way, and information will be available soon. Hewlett-Packard Company - ----------------------- HP-UX versions 1.01, 10.10, and 10.20 are vulnerable. Solution: Do not run rpc.ypupdated. rpc.ypupdated is used when adding or modifying the public:private key pair in the NIS map public key.byname via the chkey command interface. rpc.ypupdated should ONLY be run while changes are being made, then terminated when the changes are complete. Make sure you re-kill rpc.ypupdated after each reboot. NEC Corporation - --------------- OS Version Status - ------------------ ------------ -------------------------- EWS-UX/V(Rel4.0) R1.x - R2.x not vulnerable R3.x - R6.x vulnerable EWS-UX/V(Rel4.2) R7.x - R10.x vulnerable EWS-UX/V(Rel4.2MP) R10.x vulnerable UP-UX/V R2.x not vulnerable R3.x - R4.x vulnerable UP-UX/V(Rel4.2MP) R5.x - R7.x vulnerable UX/4800 R11.x vulnerable - --------------------------------------------------------------- The following is a workaround for 48 series. ypupdated program is started by the /etc/rc2.d/S75rpc script. First, determine if the server is running, killing it if it is. Then, rename ypupdated so that the /etc/rc2.d/S75rpc script will not find and therefore start it when the system reboots. # uname -a UNIX_System_V testux 4.2 1 R4000 r4000 # /sbin/ps -ef | /usr/bin/grep ypupdated root 359 1 0 08:20:05 ? 0:00 /usr/lib/netsvc/yp/ypupdated root 19938 836 0 23:13:20 pts/1 0:00 /usr/bin/grep ypupdated # /usr/bin/kill 359 # /sbin/mv /usr/lib/netsvc/yp/ypupdated /usr/lib/netsvc/yp/ypupdated.CA-95:17 # /usr/bin/chmod 0 /usr/lib/netsvc/yp/ypupdated.CA-95:17 -------------------------- Contacts for further information: E-mail:UX48-security-support@nec.co.jp Open Software Foundation - ------------------------ YP/NIS is not part of the OSF/1 Version 1.3 offering. Hence, OSF/1 Version 1.3 is not vulnerable. Sequent Computer Systems - ------------------------ Sequent does not support the product referred to in this advisory, and as such is not vulnerable. Silicon Graphics Inc. (SGI) - --------------------------- IRIX 3.x, 4.x, 5.0.x, 5.1.x, 5.2: vulnerable. Turn off rpc.ypudated in inetd.conf; it is shipped with this turned on. IRIX 5.3, 6.0, 6.0.1: rpc.ypupdated was off as distributed. Turn off if you have turned it on. Solbourne - --------- Not vulnerable. Sun Microsystems, Inc. - ---------------------- SunOS 4.1.X is vulnerable. [Note from CERT Coordination Center: We have examined Solaris and found that Solaris 2.x is not shipped with NIS support and the vulnerability is not present. There is an extra software package named the "Solaris Name ServiceTransition Kit" which in version 1.2, the current version, does not containthe rpc.ypupdated program and is therefore not vulnerable. However, version1.0 of the Solaris Name Service Transition Kit does contain rpc.ypupdated and is therefore presumed to be vulnerable.] -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAwUBMM8qwtH6sbnW3Io9AQG4ZgQAiL2i6+OyXnUOrqKbhHFvkX22WGau6LhQ MzIYhUvs+oFNekcmZ6u9H86nZxQxXfC1i+tDhTpZC5a75SJ85YlLdgnnX+I9alGw K9sNKeLjsB4jB2BHmOPupJcJdqa73Ny5K4oD6YmVDptgUg70lqF1ztjPEPkJMlxB 9LZrUeUw9+A= =QSDk -----END PGP SIGNATURE----- **************************************************************************** * * * The point of contact for NIPRNET security-related incidents is the * * Security Coordination Center (SCC). * * * * E-mail address: SCC@NIC.DDN.MIL * * * * Telephone: 1-(800)-365-3642 * * * * NIC Help Desk personnel are available from 7:00 a.m.-7:00 p.m. EST, * * Monday through Friday except on federal holidays. * * * **************************************************************************** PLEASE NOTE: Some users outside of the DOD computing communities may receive DISN Security Bulletins. If you are not part of the DOD community, please contact your agency's incident response team to report incidents. Your agency's team will coordinate with DOD. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained by sending email to docserver@first.org with an empty subject line and a message body containing the line: send first-contacts. This document was prepared as an service to the DOD community. Neither the United States Government nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government. The opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes.