Published:
20 November 2001
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2001.491 -- CERT Summary CS-2001-04 CERT Summary 21 November 2001 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Summary Vendor: CERT/CC - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- CERT Summary CS-2001-04 November 20, 2001 Each quarter, the CERT Coordination Center (CERT/CC) issues the CERT Summary to draw attention to the types of attacks reported to our incident response team, as well as 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: CERT Summaries http://www.cert.org/summaries/ ______________________________________________________________________ Recent Activity Since the last regularly scheduled CERT summary, issued in August 2001 (CS-2001-03), we have seen a new worm known as "Nimda," as well as active exploitation of a vulnerability in Microsft DNS servers. In addition, we have published a paper on denial of service trends, issued a new PGP key, and updated the UNIX Security Checklist. For more current information on activity being reported to the CERT/CC, please visit the CERT/CC Current Activity page. The Current Activity page is a regularly updated summary of the most frequent, high-impact types of security incidents and vulnerabilities being reported to the CERT/CC. The information on the Current Activity page is reviewed and updated as reporting trends change. CERT/CC Current Activity http://www.cert.org/current/current_activity.html 1. W32/Nimda Worm Over the past several months, we have received reports of malicious code known as the "W32/Nimda Worm." This worm can propogate itself via several methods, including email, network shares, or by visiting an infected web site. On September 18, the CERT/CC issued an advisory on Nimda. CERT Advisory CA-2001-26: Nimda Worm http://www.cert.org/advisories/CA-2001-26.html 2. Exploitation of Vulnerability in SSH1 CRC-32 Compensation Attack Detector The CERT/CC has received multiple reports of systems being compromised via the CRC-32 compensation attack detector vulnerability (VU#945216). On November 5, the CERT/CC released an incident note which describes system compromises via a vulnerability in the SSH1 (Secure Shell Protocol v1) CRC-32 attack detection code. Consequentially, we are also receiving reports of increased scanning activity for the SSH service (22/tcp). Incident Note IN 2001-12: Exploitation of vulnerability in SSH1 CRC-32 compensation attack detector http://www.cert.org/incident_notes/IN-2001-12.html Vulnerability Note #945216: SSH CRC32 attack detection code contains remote integer overflow http://www.kb.cert.org/vuls/id/945216 3. DNS Cache Poisoning in Microsoft DNS Servers The CERT/CC has received reports from sites experiencing cache corruption on systems running Microsoft DNS Server. We issued an incident note which describes this corruption and its impact on systems. The default configuration of this software allows data from malicious or incorrectly configured DNS servers to be cached by a Microsoft DNS server. This corruption can result in erroneous DNS information being returned to clients which use this server. Incident Note IN-2001-11: Cache Corruption on Microsoft DNS Servers http://www.cert.org/incident_notes/IN-2001-11.html Vulnerability Note #109475: Microsoft Windows NT and 2000 Domain Name Servers allow non-authoritative RRs to be cached by default http://www.kb.cert.org/vuls/id/109475 4. Trends In Denial Of Service Attack Technology This paper describes the current and possible future states of denial of service (DoS) technology. This document is in Adobe Acrobat format, and requires Acrobat Reader. Trends In Denial Of Service Attack Technology http://www.cert.org/archive/pdf/DoS_trends.pdf ______________________________________________________________________ UNIX Security Checklist Version 2.0 The CERT Coordination Center and the Australian Computer Emergency Response Team (AusCERT) have jointly published version 2.0 of the UNIX Security Checklist which details steps to improve the security of UNIX Operating Systems. We encourage system administrators to review all sections of this document and, if appropriate, modify their systems accordingly to fix potential weaknesses. AUSCERT UNIX Security Checklist http://www.cert.org/tech_tips/AUSCERT_checklist2.0.html ______________________________________________________________________ New CERT/CC PGP Key On October 1, the CERT/CC issued a new PGP key, which should be used when sending sensitive information to the CERT/CC. CERT/CC PGP Public Key https://www.cert.org/pgp/cert_pgp_key.asc Sending Sensitive Information To The CERT/CC http://www.cert.org/contact_cert/encryptmail.html ______________________________________________________________________ What's New and Updated Since the last CERT Summary, we have published new and updated * Advisories http://www.cert.org/advisories/ * Congressional Testimony http://www.cert.org/congressional_testimony/ * Incident Notes http://www.cert.org/incident_notes/ * CERT/CC Statistics http://www.cert.org/stats/cert_stats.html * Tech Tips http://www.cert.org/tech_tips/ * Training Schedule http:/www.cert.org/training/ * UNIX Security Checklist v2.0 http://www.cert.org/tech_tips/unix_security_checklist2.0.html ______________________________________________________________________ This document is available from: http://www.cert.org/summaries/CS-2001-04.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/CC personnel answer the hotline 08:00-17:00 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 subscribe to the CERT mailing list for advisories and bulletins, send email to majordomo@cert.org. Please include in the body of your message subscribe cert-advisory * "CERT" and "CERT Coordination Center" are 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. _________________________________________________________________ Conditions for use, disclaimers, and sponsorship information Copyright ©2001 Carnegie Mellon University. - -----BEGIN PGP SIGNATURE----- Version: PGP 6.5.8 iQCVAwUBO/qnUKCVPMXQI2HJAQFqJwP9Fdg7Z6LrdCAGgshO9zPojFjt/yV95bk8 dzt+RfWC/4sSuFipx1Db6c3UvBUwIMqW+JaryT21haHLWRatkgWGw/89hTsBfY5J iEgPc+sRagEJ/w6gOas5N2B+4uNApXU9Fj0S0IgfaLulIfixtkfJkKUAHVjFxqAk MRViE3BdE9A= =OX1Z - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBO/uQwSh9+71yA2DNAQHBgwP/dkaVaIiHML88wZBJOcXrKtwwlVrlWBgh kqHccT3IvTTwJWoqlm2rdVThMGBzjSyWRhqsgknDIldbbqTE5pfzwxK8udXqGzxs A5Ovi4rLbKiuy6EYg6rHxWVqh7NiKNg1i2xkCAUyFpM43aelYdNGpyyqCEeZEyI5 Xs3Za34D/RM= =B9t2 -----END PGP SIGNATURE-----