-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =============================================================================== >> CERT-NL, 01-Mar-2000 << >> All CERT-NL information has been moved to http://cert.surfnet.nl. Links << >> to CERT-NL information contained in this advisory are therefore outdated. << >> << >> CERT-NL also has stopped the CERT-CC-Mirror service. Due to this the << >> links to the CERT-CC mirror are obsolete. Visit the CERT-CC site for the << >> complete CERT-CC advisory texts: http://www.cert.org << =============================================================================== =============================================================================== Security Advisory CERT-NL =============================================================================== Author/Source : Nico de Koo Index : S-95-13 Distribution : World Page : 1 Classification: External Version: 1 Subject : Logdaemon/FreeBSD vulnerability in S/Key Date : 15-Jun-95 =============================================================================== CERT-NL received the following bulletin, issued by CERT as: CERT Vendor-Initiated Bulletin VB-95:04 June 14, 1995 Topic: Logdaemon/FreeBSD vulnerability in S/Key Source: Wietse Venema (wietse@wzv.win.tue.nl) To aid in the wide distribution of essential security information, the CERT Coordination Center is forwarding the following information from Wietse Venema, who urges you to act on this information as soon as possible. Please contact Wietse Venema if you have any questions or need further information. ========================FORWARDED TEXT STARTS HERE============================ A vulnerability exists in my own S/Key software enhancements. Since these enhancements are in wide-spread use, a public announcement is appropriate. The vulnerability affects the following products: FreeBSD version 1.1.5.1 FreeBSD version 2.0 logdaemon versions before 4.9 I recommend that users of this software follow the instructions given below in section III. - ----------------------------------------------------------------------------- I. Description An obscure oversight was found in software that I derived from the S/Key software from Bellcore (Bell Communications Research). Analysis revealed that my oversight introduces a vulnerability. Note: the vulnerability is not present in the original S/Key software from Bellcore. II. Impact Unauthorized users can gain privileges of other users, possibly including root. The vulnerability can be exploited only by users with a valid account. It cannot be exploited by arbitrary remote users. The vulnerability can affect all FreeBSD 1.1.5.1 and FreeBSD 2.0 implementations and all Logdaemon versions before 4.9. The problem exists only when S/Key logins are supported (which is the default for FreeBSD). Sites with S/Key logins disabled are not vulnerable. III. Solution Logdaemon users: ================ Upgrade to version 4.9 URL ftp://ftp.win.tue.nl/pub/security/logdaemon-4.9.tar.gz. MD5 checksum 3d01ecc63f621f962a0965f13fe57ca6 To plug the hole, build and install the ftpd, rexecd and login programs. If you installed the keysu and skeysh commands, these need to be replaced too. FreeBSD 1.1.5.1 and FreeBSD 2.0 users: ====================================== Retrieve the corrected files that match the system you are running: URL ftp://ftp.cdrom.com/pub/FreeBSD/CERT/libskey-1.1.5.1.tgz MD5 checksum bf3a8e8e10d63da9de550b0332107302 URL ftp://ftp.cdrom.com/pub/FreeBSD/CERT/libskey-2.0.tgz MD5 checksum d58a17f4216c3ee9b9831dbfcff93d29 Unpack the tar archive and follow the instructions in the README file. FreeBSD current users: ====================== Update your /usr/src/lib/libskey sources and rebuild and install libskey (both shared and non-shared versions). The vulnerability has been fixed with FreeBSD 2.0.5. - ----------------------------------------------------------------------------- S/KEY is a trademark of Bellcore (Bell Communications Research). Wietse Venema appreciates helpful assistance with the resolution of this vulnerability from CERT/CC; Rodney W. Grimes, FreeBSD Core Team Member; Guido van Rooij, Philips Communication and Processing Services; Walter Belgers. =========================FORWARDED TEXT ENDS HERE============================= We thank Wietse Venema and CERT/CC for providing us the information regarding this Security Bulletin ============================================================================== 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://cert.surfnet.nl/ 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 22 92 35 64 ALTIJD BEREIKBAAR EMERGENCIES : +31 6 22 92 35 64 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: PGP 6.5.1i iQA/AwUBOL6IFTSYjBqwfc9jEQJcdgCgusqZONz+u8jPn04oZlV3DkbLUrkAoLI4 6ljckLhN2n9QylZpyeNOLJMA =1L49 -----END PGP SIGNATURE-----