-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Network Time Protocol (NTP) Vulnerabilities April 17, 2001 18:00 GMT Number L-071 [Revision A 10/29/2001 Added Sun Bulletin #211] [Revision B 11/21/2001 Modified Platform's FreeBSD section] ______________________________________________________________________________ PROBLEM: The Network Time Protocol (NTP) codes of certain vendors are vulnerable to a buffer overflow attack. PLATFORM: Hewlett-Packard: HP9000 Series 700/800 running HP-UX releases 10.XX and 11.XX. Red Hat: Red Hat Linux 6.2 and earlier (for xntpd). Red Hat Linux 7.0 (for ntpd). NetBSD: NetBSD prior to 1.4. NetBSD 1.4 and 1.5. NetBSD-CURRENT prior to 2001-04-05. FreeBSD: FreeBSD 3.x (all releases). FreeBSD 4.x (all releases prior to 4.3-RELEASE). FreeBSD 3.5-STABLE and 4.2-STABLE prior to the correction date 2001-04-06. FreeBSD ports collection prior to the correction date 2001-04-06. Caldera: OpenLinux 2.3 (All packages previous to xntp-3.5.93e-5) OpenLinux eServer 2.3.1 and OpenLinux eBuilder (All packages previous to xntp-3.5.93e-5) OpenLinux eDesktop 2.4 (All packages previous to xntp-4.0.97-2) Sun: Solaris 8, 7, and 2.6. SunOS 5.8, 5.7, and 5.6. DAMAGE: A remote intruder can use the buffer overflow to cause the NTP code, and even the machine that is running NTP, to crash. It is possible that the buffer overflow can be used to execute arbritrary code. If the NTP daemon is running as root, then this could lead to a root compromise. SOLUTION: Obtain your particular vendor’s directions from the vendor’s web site and follow the vendor’s suggestions. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. The listed vendors have determined that their ASSESSMENT: codes are vulnerable. The vulnerabilities and detailed exploits have been discussed in public forums. ______________________________________________________________________________ The NTP code sets and maintains a UNIX system’s time-of-day in agreement with Internet standard time servers. NTP uses the Internet Protocol (IP) and User Datagram Protocol (UDP) for sending and receiving the time-of-day information. There are buffer overflow attacks that can cause some NTP servers to crash, leading to a root compromise. CIAC has included the vendor information we know about in this bulletin. While CIAC will add new vendor information as we receive it, you should always check your vendor’s web site to insure you have the latest information. Hewlett-Packard: Use your browser to get to the HP IT Resource Center page at: http://itrc.hp.com Under the Maintenance/Support menu, click on the "search technical knowledge base" link. Login using your ID and password. Check with your system administrator to see if you have an existing login or click on the "register now" link in the "New Users - Please Register" section. Once you are in the "Technical Knowledge Base" page, select the "Security Bulletins" link in the "HP-UX Software" section. Do a "Search By Keyword" for "xntpd", and look for "Security Advisory #0148, 06 Apr. ‘01" in the search results. This is the bulletin "Sec. Vulnerability in xntpd(1M)". Red Hat Linux: Use your browser to get to the Red Hat Linux Errata page at: http://www.redhat.com/support/errata/ Under the "General Red Hat Linux Errata" section, go to the "Version 7.0 (Guinness)" subsection and click on the "Security Advisories" link. This will bring you to the "Red Hat Linux 7.0 Security Advisories" page. Click on the "xntp3 (RSHA-2001-045)" link under the "Name" column to get to the security bulletin "Network Time Daemon (ntpd) has potential remote root exploit." NetBSD: Use your browser to get to the NetBSD Project’s "Security and NetBSD" page at: http://www.netbsd.org/Security/ Click on the "advisory archive" link to get to the advisory "NetBSD- SA2001-004 Buffer overflow in NTP daemon". FreeBSD: Use your browser to get to the "FreeBSD Security Information" page at: http://www.freebsd.org/security/security.html Under the "Table of Contents" section, click on the "FreeBSD Security Advisories" link. In the "FreeBSD Security Advisories" section, click on the ""FTP_Site" link. Double-click on the link "FreeBSD-SA-01:31.ntpd.asc" to download the FreeBSD-SA-01:31 advisory "ntpd contains potential remote compromise". Caldera: Use your browser to get to Caldera's "Security Advisories" page at: http://www.calderasystems.com/support/security/ Click on the "CSSA-2001-013.0" link for the "Remote root exploit in ntpd" security advisory. Sun: Use your browser to get to the "Sun Microsystems" page at: http://www.sun.com/ Select the "Site Index" tab at the top of the page to get to the "Sun.Com Site Index" page. Select the letter "S" in the alphabetical listing at the top of the page. Scroll down the page to the "Sunsolve Online Support" entry, and click on it. Once you are in the "SunSolve Online" page, go to the "SunSolve Contents" page and click on the "Security Bulletin Archive". Once you are in the "Security Information/Security Bulletin" page, click on Bulletin numbered 211, topic "xntpd". _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Hewlett-Packard, Red Hat, NetBSD, FreeBSD, Caldera, and Sun 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 (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. 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 via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, 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 or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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