************************************************************************** Security Bulletin 9612 DISA Defense Communications System May 30, 1996 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 96-10 Release date: May 29, 1996, 4:30 PM EDT (GMT -4) SUBJECT: YPX Attacks against .GOV and .MIL Sites SUMMARY: This bulletin contains information regarding recently detected widespread sunrpc attempts against military and DOD targets. Sunrpc service includes NIS, NFS, and showmount services. BACKGROUND: Various DOD elements have recently detected YP/NIS widespread password grabbing attempts. The source sites in these attacks were one .com site and one .net site. In one instance an intruder uploaded malicious software to a .mil site via FTP. The intruder then telneted to the site in order to compile and run the code. All source code was subsequently deleted. The intruder stored the compiled software in a directory named "...". The software itself was named pimpx. The pimpx program is a sweep tool which takes a list of systems from a file, and executes ypx, a tool which connects to the mail port of each system. From the mail header, the pimpx program will then try to guess the NIS domain name, and retrieve the NIS password file. Ypx is well known and widely available. The input file for pimpx has been identified as gov. Gov contained 43221 individual lines of entries probably extracted from the NIC. As a precaution all are encouraged to apply the guidelines in the RECOMMENDED SOLUTIONS section below as soon as possible. IMPACT: Password files may be vulnerable to download from unauthorized Internet sites. RECOMMENDED SOLUTIONS: I) Verify security on yp server: a) Install shadowed password files (if available). b) Run crack against the password files on all file servers. Change passwords for those that can be easily cracked. c) Check the NIS domain name to ensure it doesn't match the actual domain name. If it does, change it immediately! Please reference the ASSIST bulletins assist.603 and assista.603 which describe the UNIX sendmail vulnerability. These bulletins can be found at the ASSIST FTP site: ftp.assist.mil/pub/bulletins.newsletters/assist.bulletins/ assist96/assist.603 and assista.603. d) For NFS servers, check to see if any writable file systems are exported to the world (everyone). Ensure that filesystems in the export list use the -access parameter. e) Download a copy of "Security Profile Inspector" (SPI) for UNIX. SPI will evaluate and test for weaknesses in your various network services (e.g., NFS & NIS) SPI can be found at the ASSIST anonymous FTP site: ftp.assist.mil/pub/tools/unix/spi/ II) Analyze audit records or logs for unauthorized connections or suspicious activity. a) Search for files called pimpx, ypx, or gov. b) Search for unknown users logging into your system via a legitimate user's account. c) Watch for unusual network load increase. III) Report any unauthorized connections or suspicious activity to the appropriate response team (AFCERT, NAVCIRT, ACERT, ASSIST, etc). See ASSIST Contact Information below. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ASSIST would like to thank AFCERT for contributing 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 ftp.assist.mil (IP address 199.211.123.12). Note: ftp.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 327-4735 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. 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- -----END PGP PUBLIC KEY BLOCK----- -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAwUBMayxJdH6sbnW3Io9AQE91AQAvtGum4vVSl7I8nv35b+JDZ26go9Diue+ +NOjO/Lk03CU8zMHx+FCYQbC/3bn70ym8M/qKWf+lu7PO+slO9HEwGH8WOvdyh4e AOq+Kx3qAvihCRkknN4ima+yKtLxBfeZNm+Bmj3NpAMrSZ5hAPdAE/G6Tz5M1Z74 HMh759gYu94= =xR6a -----END PGP SIGNATURE----- -- _______ A S S I S T | / Automated Systems Security Incident Support Team | / Duty phone: +1 800 357 4231 (DSN 327 4700) 24hr | / Integritas Commercial +1 703 607 4700 24hr | < et 24hr pager: +1 800 791 4857 | \ Celeritas BBS: +1 703 607 4710 (DSN 327 4710) | \ Unclass FAX: +1 703 607 4735 (DSN 327 4735) | \ e-mail: ASSIST@ASSIST.MIL ------- Anonymous FTP: FTP.ASSIST.MIL (IP 199.211.123.12) **************************************************************************** * * * 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.