-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - -------------------------------------------------------------------------- CONECTIVA LINUX SECURITY ANNOUNCEMENT - -------------------------------------------------------------------------- PACKAGE : vnc SUMMARY : Vulnerabilties in cookies and random challenge generations DATE : 2003-05-05 17:49:00 ID : CLA-2003:640 RELEVANT RELEASES : 7.0, 8 - ------------------------------------------------------------------------- DESCRIPTION Virtual Network Computing (VNC) is a tool that provides remote display viewing/controlling. This update fixes two vulnerabilities found in VNC that affect the versions distributed with Conectiva Linux 7.0 and 8: - Weak challenge number generation[1] VNC uses a challenge-response schema for authentication, but it uses the same challenge for multiple connections that are done in an interval of one second. An attacker can exploit this vulnerability by sniffing the connection and using the same challenge/response of a valid conection to gain access without having a valid account in the vnc server. This vulnerability was fixed in TightVNC 1.2.6. The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2002-1336 to this issue[2]. - Weak Xcookie generation When the VNC server acts as an XServer, it generates a MIT-MAGIC-COOKIE[4] to authenticate users. VNC versions up to 3.3.3r2-21 generate such a cookie in an unsafe manner (not randomly enough), allowing attackers to more easily guess it. A remote attacker can access the vnc server without having permission to do so if it knows the cookie value. The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2002-1511 to this issue[3]. SOLUTION All vnc users should upgrade. REFERENCES: 1.http://marc.theaimsgroup.com/?l=bugtraq&m=102753170201524 2.http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-1336 3.http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-1511 4.http://www-ugrad.cs.colorado.edu/udp/xauth.html UPDATED PACKAGES ftp://atualizacoes.conectiva.com.br/7.0/RPMS/vnc-3.3.3-6U70_2cl.i386.rpm ftp://atualizacoes.conectiva.com.br/7.0/SRPMS/vnc-3.3.3-6U70_2cl.src.rp ftp://atualizacoes.conectiva.com.br/8/RPMS/vnc-3.3.3r2+tight1.2.2-6U80_1cl.i386.rpm ftp://atualizacoes.conectiva.com.br/8/RPMS/vnc-java-3.3.3r2+tight1.2.2-6U80_1cl.i386.rpm ftp://atualizacoes.conectiva.com.br/8/RPMS/vnc-server-3.3.3r2+tight1.2.2-6U80_1cl.i386.rpm ftp://atualizacoes.conectiva.com.br/8/SRPMS/vnc-3.3.3r2+tight1.2.2-6U80_1cl.src.rpm ADDITIONAL INSTRUCTIONS The apt tool can be used to perform RPM packages upgrades: - run: apt-get update - after that, execute: apt-get upgrade Detailed instructions reagarding the use of apt and upgrade examples can be found at http://distro.conectiva.com.br/atualizacoes/#apt?idioma=en - ------------------------------------------------------------------------- All packages are signed with Conectiva's GPG key. The key and instructions on how to import it can be found at http://distro.conectiva.com.br/seguranca/chave/?idioma=en Instructions on how to check the signatures of the RPM packages can be found at http://distro.conectiva.com.br/seguranca/politica/?idioma=en - ------------------------------------------------------------------------- All our advisories and generic update instructions can be viewed at http://distro.conectiva.com.br/atualizacoes/?idioma=en - ------------------------------------------------------------------------- Copyright (c) 2003 Conectiva Inc. http://www.conectiva.com - ------------------------------------------------------------------------- subscribe: conectiva-updates-subscribeat_private unsubscribe: conectiva-updates-unsubscribeat_private -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE+ttQa42jd0JmAcZARAn8MAKCLvSXU50AY6d3Nv6CjP/HlDvlKOACg4pIl vzsBO1oU0UlZ6pFypnZhb3o= =U+Zi -----END PGP SIGNATURE-----
This archive was generated by hypermail 2b30 : Mon May 05 2003 - 14:30:10 PDT