-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 CERT Summary CS-98.08 December 14, 1998 The CERT Coordination Center periodically issues the CERT Summary to draw attention to the types of attacks currently being reported to our incident response team, as well as to other noteworthy incident and vulnerability information. The summary includes pointers to sources of information for dealing with the problems. Past CERT Summaries are available from http://www.cert.org/summaries/ ______________________________________________________________________ Recent Activity Since the last CERT Summary, issued in August 1998 (CS-98.07), we have seen these trends in incidents reported to us. 1. Vulnerability in mountd We have seen many reports of this vulnerability being exploited on NFS servers running certain implementations of mountd, primarily Linux. On some systems, the vulnerable NFS server is enabled by default. This vulnerability can be exploited even if the NFS server does not export any file systems. Intruders who are able to exploit the vulnerability can do it remotely and can gain administrative access. We encourage you to review CERT Advisory CA-98.12, which describes the mountd vulnerability in more detail. The advisory is available from http://www.cert.org/advisories/CA-98.12.mountd.html 2. Spread of Windows-Based Trojan Horse Programs In recent months, we have seen the spread of Windows-based Trojan horse programs. The most frequently reported incidents involving Windows-based Trojan horse programs involve the tools Back Orifice and NetBus. We receive occasional reports of compromised machines that have one of these tools installed; however, the majority of reports involving these tools are from sites noticing intruders scanning their networks for the presence of these tools. We receive daily reports indicating that intruders are actively scanning networks to find running instances of these tools on already compromised machines. Look for the following symptoms to detect those scans: NetBus - connection request (SYN) packets to TCP port 12345 Back Orifice - UDP packets to port 31337 Keep in mind that these tools can be configured to listen on different ports. Because of this, we encourage you to investigate any unexplained network traffic. Because these tools are Trojan horses, users must install them or be tricked into installing them. To impede the proliferation of this class of tools, we encourage system administrators to educate their users about safe computing practices (e.g., only install software from trusted sources, and use virus scanning software on any newly introduced software). For more information about Back Orifice, we encourage you to review CERT Vulnerability Note VN-98.07. http://www.cert.org/vul_notes/VN-98.07.backorifice.html 3. Widespread Scans We continue to receive numerous daily reports of intruders using tools to scan networks for multiple vulnerabilities. On July 2, we published an incident note detailing this activity. This document is available at http://www.cert.org/incident_notes/IN-98.02.html Since July 2 these tools have become a bit more sophisticated. Variants of the "mscan" tool now probe for the most recent vulnerabilities including http://www.cert.org/advisories/CA-98.12.mountd.html Additionally, these tools incorporate the ability to identify a machine's architecture and operating system. 4. Scripted Tools Very recently, we have received a few reports indicating that intruders are executing widespread attacks using scripted tools to control various information-gathering and exploitation tools. The combination of functionality used by the scripted tools enables intruders to automate the process of identifying and exploiting known vulnerabilities in specific host platforms. This information is available at http://www.cert.org/incident_notes/IN-98-06.html 5. Stealth Scanning Techniques We have received a few reports indicating that intruders are using stealth scanning techniques. Stealth scanning is used by intruders to avoid detection. Details about stealth scanning techniques are available at http://www.cert.org/incident_notes/IN-98.04.html __________________________________________________________________ What's New and Updated Since the last CERT Summary, we have developed new and updated + Incident Notes + Vulnerability Notes + Advisories + Vendor-Initated Bulletins + System Survivability Research information + Incident Response Courses If you are interested in any of these, please see our What's New web page for descriptions and links: http://www.cert.org/nav/whatsnew.html __________________________________________________________________ CERT/CC Contact Information Email: cert@cert.org Phone: +1 412-268-7090 (24-hour hotline) Fax: +1 412-268-6989 Postal address: CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh PA 15213-3890 U.S.A. CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4) Monday through Friday; they are on call for emergencies during other hours, on U.S. holidays, and on weekends. Using encryption We strongly urge you to encrypt sensitive information sent by email. Our public PGP key is available from http://www.cert.org/CERT_PGP.key. If you prefer to use DES, please call the CERT hotline for more information. Getting security information CERT publications and other security information are available from our web site http://www.cert.org/. To be added to our mailing list for advisories and bulletins, send email to cert-advisory-request@cert.org and include SUBSCRIBE your-email-address in the subject of your message. Copyright 1998 Carnegie Mellon University. Conditions for use, disclaimers, and sponsorship information can be found in http://www.cert.org/legal_stuff.html. * CERT is registered in the U.S. Patent and Trademark Office __________________________________________________________________ NO WARRANTY Any material furnished by Carnegie Mellon University and the Software Engineering Institute is furnished on an "as is" basis. Carnegie Mellon University makes no warranties of any kind, either expressed or implied as to any matter including, but not limited to, warranty of fitness for a particular purpose or merchantability, exclusivity or results obtained from use of the material. Carnegie Mellon University does not make any warranty of any kind with respect to freedom from patent, trademark, or copyright infringement. -----BEGIN PGP SIGNATURE----- Version: PGP for Personal Privacy 5.0 Charset: noconv iQA/AwUBOBTFFFr9kb5qlZHQEQJhmQCfVWeXsc4OSd+ATTve7CXkPb+FV94AoPzJ apAq1keDQhh0NFlRLzQ4ROC+ =WyS1 -----END PGP SIGNATURE-----