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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2007.0139 -- [Solaris] Sun Solaris Telnet Worm 1 March 2007 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: in.telnetd Publisher: US-CERT Operating System: Solaris 10 Impact: Root Compromise Access: Remote/Unauthenticated CVE Names: CVE-2007-0882 Ref: AA-2007.0006 Original Bulletin: http://www.us-cert.gov/cas/techalerts/TA07-059A.html Comment: This worm targets the vulnerability reported previously in AusCERT advisory AA-2007.0006. AusCERT has not observed a large volume of telnet scan sources within Australia at this point. - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 National Cyber Alert System Technical Cyber Security Alert TA07-059A Sun Solaris Telnet Worm Original release date: February 28, 2007 Last revised: -- Source: US-CERT Systems Affected * Sun Solaris 10 (SunOS 5.10) * Sun "Nevada" (SunOS 5.11) Both SPARC and Intel (x86) architectures are affected. Overview A worm is exploiting a vulnerability (VU#881872) in the Sun Solaris telnet daemon (in.telnetd). I. Description A worm is exploiting a vulnerability in the telnet daemon (in.telnetd) on unpatched Sun Solaris systems. The vulnerability allows the worm (or any attacker) to log in via telnet (23/tcp) with elevated privileges. Further details about the vulnerability are available in Vulnerability Note VU#881872 (CVE-2007-0882). Because VU#881872 is trivial to exploit and sufficient technical detail is publicly available, any attacker, not just this worm, could exploit vulnerable systems. Characteristics of the worm include, but are not limited to: * Exploiting VU#881872 to log in via telnet as the users adm or lp * Changing permissions on /var/adm/wtmpx to -rw-r--rw- * Creating the directory .adm in /var/adm/sa/ * Adding .profile files to /var/adm/ and /var/spool/lp/ * Installing an authenticated backdoor shell on port 32982/tcp * Modifying crontab entries for the users adm and lp * Scanning for other hosts running telnet (23/tcp) Sun has published information about the worm in the Security Sun Alert Feed including an inoculation script that disables the telnet daemon and reverses known changes made by the worm. II. Impact VU#881872 allows remote attacker to log on to a vulnerable system via telnet and gain elevated privileges. The worm exploits this vulnerability to compromise systems as described above. Since the worm installs a backdoor shell, it is possible for an attacker with knowledge of the authentication tokens to access a compromised system and take any action with the privileges of the backdoor shell process, likely adm or lp. III. Solution Apply a patch To address VU#881872, apply the appropriate patches referenced in Sun Alert Notification 102802. Run inoculation script To recover compromised systems, Sun has provided an inoculation script that disables the telnet daemon and reverses known changes made by the worm. Note that the inoculation script only recovers from this particular worm. Running the inoculation script does not guarantee system integrity. A vulnerable system may be compromised in different ways by attackers exploiting VU#881872 or using the backdoor installed by the worm. To fully recover, it may be necessary to rebuild a compromised system using trusted software sources. For more information, see Recovering from an Incident. IV. Workarounds Until the appropriate patches can be applied, consider the following workarounds. Disable telnet Telnet can be disabled by issuing the following command as root: # /usr/sbin/svcadm disable telnet Restrict telnet access Restrict access to telnet (23/tcp) from untrusted networks such as the Internet. Use SSH instead of telnet SSH provides a comparatively more secure method for remotely logging into a system than telnet. As general advice, we recommend using SSH rather than telnet. V. References * US-CERT Vulnerability Note VU#881872 - <http://www.kb.cert.org/vuls/id/881872> * Recovering from an Incident - <http://www.cert.org/nav/recovering.html> * Sun Alert Notification 102802 - <http://sunsolve.sun.com/search/document.do?assetkey=1-26-102802-1> * Solaris in.telnetd worm seen in the wild + inoculation script - <http://blogs.sun.com/security/entry/solaris_in_telnetd_worm_seen> * inoculate.local - <http://blogs.sun.com/security/resource/inoculate.local> * CVE-2007-0882 - <http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-0882> ____________________________________________________________________ The most recent version of this document can be found at: <http://www.us-cert.gov/cas/techalerts/TA07-059A.html> ____________________________________________________________________ Feedback can be directed to US-CERT Technical Staff. Please send email to <cert@cert.org> with "TA07-059A Feedback VU#881872" in the subject. ____________________________________________________________________ For instructions on subscribing to or unsubscribing from this mailing list, visit <http://www.us-cert.gov/cas/signup.html>. ____________________________________________________________________ Produced 2007 by US-CERT, a government organization. Terms of use: <http://www.us-cert.gov/legal.html> ____________________________________________________________________ Revision History February 28, 2007: Initial release - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iQEVAwUBReYctOxOF3G+ig+rAQKGUAf+LY2zbs3k8mx3mYhgtpLWCCOo5wDjd90a g+apWM4B9qEsAvlIsI/tWof5xSf682D7Yx47xwDDxUyIswHkovGaIWQ7TKmew1Be On7KUFSi0fHQ9Su4536COmr3aCOoeXhPpIIC8nFyb9rZ22aax6LowxH4THU1uFRO vITWFHKuWkSW75D4WQ9z19m1cdkXf2Y6SC9UcqADdImFo0ZG/mVzQ8as1sb3nHM7 0cBje0Dt4rEUtMkgBRrIMqoa1FquJXnLT0YnUtQp914SguxhD5sB/shjiIrttpVq uROeI77nsfGzAyWLes2K/fDik4/HJLIgiTpnONBTrXNYuuTsfKOJ0Q== =rcWZ - -----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. NOTE: Third Party Rights 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 follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. 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 author's website 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/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 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 member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQCVAwUBReYk5ih9+71yA2DNAQLejAQAneQzKER9ivL6L28Wbs9l1ezvqQn5Mhyu J6C+pBRmf96V2hQk9gU75npbwRlqhZ3yuqew0NqHLCemyd9Fpuw5T4o97sh0ZQ2n 4Mny8jfteIt+t4FXmAHjIMuF6QfEH7BKMYNnfpZesnjWLo8GJGHJIpudLwF/1OzT L8B58JswpdQ= =E6cS -----END PGP SIGNATURE-----