-----BEGIN PGP SIGNED MESSAGE----- =============================================================================== Security Advisory CERT-NL =============================================================================== Author/Source : Teun Nijssen Index : S-99-33 Distribution : World Page : 1 Classification: External Version: 1 Subject : CERT Summary Date : 03-Sep-99 =============================================================================== By courtesy of CERT/CC we received a CERT Summary. CERT-NL does not always replicate this material, as interested parties are expected to read them after being attended to its arrival by the "notifier'. This summary (mainly the "recent activities" part is deemed) of sufficient interest to distribute it widely. CERT Summary CS-99-03 August 31, 1999 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 http://www.cert.org/summaries/ ______________________________________________________________________ New CERT/CC PGP Key On October 4, 1999, the current PGP key for the CERT/CC will be replaced with a new PGP key. For more information, see http://www.cert.org/pgp/newpgp.html ______________________________________________________________________ New "CERT/CC Current Activity" Web Page The CERT/CC Current Activity web page is a regularly updated summary of the most frequent, high-impact types of security incidents and vulnerabilities currently being reported to the CERT/CC. It is available from http://www.cert.org/current/current_activity.html The information on the Current Activity page will be reviewed and updated as reporting trends change. ______________________________________________________________________ Recent Activity Since the last CERT summary, issued in May 1999 (CS-99-02), we have noted several vulnerabilities in RPC services, and we have analyzed and published information regarding the ExploreZip worm. We also continue to see widespread scans for known vulnerabilites. Protect your systems. Use current software versions, install patches as they become available, and update your scanning tools and anti-virus software with the latest virus signatures or definitions. Be cautious of unsolicited documents or executable programs received in electronic mail. Be wary of software that comes from untrusted sources. 1. RPC Vulnerabilities We have received many reports of exploitations involving three RPC vulnerabilties. Such exploitations can lead to root compromise on systems that implement these RPC services. Analysis has shown that similar artifacts have been found on compromised systems. The vulnerable services are rpc.cmsd Remote and local users can execute arbitrary code with the privileges of the rpc.cmsd daemon, typically root. This vulnerability is being exploited in a significant number of incidents reported to the CERT/CC. For more information see CERT Incident Note 99-04 http://www.cert.org/incident_notes/IN-99-04.html CERT Advisory CA-99-08 http://www.cert.org/advisories/CA-99-08-cmsd.html statd and automoutd Vulnerabilities in these two services are being used together by intruders to gain access to vulnerable systems. The first vulnerability is in rpc.statd, a program used to communicate state changes among NFS clients and servers. The second vulnerability is in automountd, a program used to automatically mount certain types of file systems. The vulnerability in rpc.statd may allow a remote intruder to call arbitrary RPC services with the privileges of the rpc.statd process, typically root. The vulnerablility in automountd may allow a local intruder to execute arbitrary commands with the privileges of the automountd service. By combining attacks exploiting these two vulnerabilities, a remote intruder is able to execute arbitrary commands with the privileges of the automountd service. For more information see CERT Incident Note 99-04 http://www.cert.org/incident_notes/IN-99-04.html CERT Advisory CA-99-05 http://www.cert.org/advisories/CA-99-05-statd-automountd.html ttbserverd The ToolTalk database server (rpc.ttdbserverd) is an ONC RPC service that manages objects needed for the operation of the ToolTalk service. ToolTalk-enabled processes communicate with each other using RPC calls to this program, which runs on each ToolTalk-enabled host. This program is a standard component of CDE (Common Desktop Environment), which is a standard component of many commercial Unix operating systems. Due to an implementation fault in rpc.ttdbserverd, it is possible for a malicious remote client to formulate an RPC message that can lead to a buffer overflow. This buffer overflow can result in an attacker gaining total control of the ttdbserver process. An intruder may be able to use this control to gain root-level privileges. CERT Incident Note 99-04 http://www.cert.org/incident_notes/IN-99-04.html CERT Advisory CA-98-11 http://www.cert.org/advisories/CA-98.11.tooltalk.html 2. Virus and Trojan Horse Activity We continue to see reports of virus activity. Current versions of anti-virus software can help to protect your systems from these viruses. It is important to take great caution with any email or Usenet attachments that contain executable content. If you receive a message containing attachments, scan the message file with anti-virus software before you open or run the file. Doing this does not guarantee that the contents of the file are safe, but it lowers your risk of virus infection by checking for viruses and Trojan horses that your scanning software can detect. ExploreZip.exe The ExploreZip program is a Trojan horse affecting Windows 95/98/NT systems. It modifies system files and destroys files. For ExploreZip to work, a person must open or run an infected email attachment, which allows the program to install a copy of itself on the victim's computer and enables further propagation. ExploreZip may also behave as a worm, propagating to other network machines without human interaction. For more information see CERT Advisory CA-99-06 ExploreZip Trojan Horse Program http://www.cert.org/advisories/CA-99-06-explorezip.html CERT Advisory CA-99-02 Trojan Horses http://www.cert.org/advisories/CA-99-02-Trojan-Horses.html 3. Continued Widespread Scans We are still receiving daily reports of intruders using tools to scan networks for multiple vulnerabilities. Intruder scanning tools continue to become more sophisticated, varying from scripted tools and stealth scanning techniques to a tool that incorporates probes for known vulnerabilities, remote operating system identification, and automated exploitation attempts. For more information, see "sscan" Scanning Tool http://www.cert.org/incident_notes/IN-99-01.html Automated Scanning and Exploitation http://www.cert.org/incident_notes/IN-98-06.html Probes with Spoofed IP Addresses http://www.cert.org/incident_notes/IN-98-05.html Advanced Scanning http://www.cert.org/incident_notes/IN-98.04.html New Tools Used for Widespread Scans http://www.cert.org/incident_notes/IN-98.02.html The most frequent reports involve well-known vulnerabilities in mountd, IMAP, POP3, and several RPC services. These services are installed and enabled by default in some operating systems. See the following advisories for more information: sunrpc (TCP port 111) and mountd (635) http://www.cert.org/advisories/CA-98.12.mountd.html http://www.cert.org/incident_notes/IN-99-04.html IMAP (TCP port 143) http://www.cert.org/advisories/CA-98.09.imapd.html POP3 (TCP port 110) http://www.cert.org/advisories/CA-98.08.qpopper_vul.html DNS (TCP port 53 [domain]) http://www.cert.org/advisories/CA-98.05.bind_problems.html http://www.cert.org/advisories/CA-97.22.bind.html These scans involve known vulnerabilities for which patches are available. Protect your systems by making sure that they are properly secured. ============================================================================== CERT-NL is the Computer Emergency Response Team for SURFnet customers. SURFnet is the Dutch network for educational, research and related institutes. CERT-NL is a member of the Forum of Incident Response and Security Teams (FIRST). All CERT-NL material is available under: http://www.surfnet.nl/surfnet/security/cert-nl.html ftp://ftp.surfnet.nl/surfnet/net-security In case of computer or network security problems please contact your local CERT/security-team or CERT-NL (if your institute is NOT a SURFnet customer please address the appropriate (local) CERT/security-team). CERT-NL is one/two hour(s) ahead of UTC (GMT) in winter/summer, i.e. UTC+0100 in winter and UTC+0200 in summer (DST). Email: cert-nl@surfnet.nl ATTENDED REGULARLY ALL DAYS Phone: +31 302 305 305 BUSINESS HOURS ONLY Fax: +31 302 305 329 BUSINESS HOURS ONLY Snailmail: SURFnet bv Attn. CERT-NL P.O. Box 19035 NL - 3501 DA UTRECHT The Netherlands NOODGEVALLEN: 06 52 87 92 82 ALTIJD BEREIKBAAR EMERGENCIES : +31 6 52 87 92 82 ATTENDED AT ALL TIMES CERT-NL'S EMERGENCY PHONENUMBER IS ONLY TO BE USED IN CASE OF EMERGENCIES: THE SURFNET HELPDESK OPERATING THE EMERGENCY NUMBER HAS A *FIXED* PROCEDURE FOR DEALING WITH YOUR ALERT AND WILL IN REGULAR CASES RELAY IT TO CERT-NL IN AN APPROPRIATE MANNER. CERT-NL WILL THEN CONTACT YOU. ============================================================================== -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.0.2i iQCVAwUBN8/YofE6s6q7Tf4RAQEsTgQAkcQyEznYLOot15Y+XbLm65LLtOMKuJ6H QZ/kvK2erK8N4sy3hpAFXIWhG2kyrxD7nfAFXKBNlXXvHvYr2aY6zztaNbp/tA2c oVqeDjtDiIAVvE82ekmXvue2nrSIPjsk/PAtOw0H9lzsuCRR0h5i25kP3bBwdgLX roDMCuuSLt4= =DKVJ -----END PGP SIGNATURE-----