OpenSSH 3.0.2 fixes UseLogin vulnerability

 Date: Tue, 4 Dec 2001 13:48:19 +0100 From: Markus Friedl  Reply-To: openssh@openbsd.org To: openssh-unix-announce@mindrot.org, openssh-unix-dev@mindrot.org Cc: openssh@openbsd.org, lwn@lwn.net, announce@openbsd.org, misc@openbsd.org,      dengue@deadly.org, news@linuxsecurity.com Subject: OpenSSH 3.0.2 fixes UseLogin vulnerability  OpenSSH 3.0.2 has just been released. It will be available from the mirrors listed at http://www.openssh.com/ shortly.  OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0 implementation and includes sftp client and server support.  We would like to thank the OpenSSH community for their continued support and encouragement.  Important Changes: ==================          This release fixes a vulnerability in the UseLogin option         of OpenSSH.  This option is not enabled in the default         installation of OpenSSH.          However, if UseLogin is enabled by the administrator, all         versions of OpenSSH prior to 3.0.2 may be vulnerable to         local attacks.          The vulnerability allows local users to pass environment         variables (e.g. LD_PRELOAD) to the login process.  The login         process is run with the same privilege as sshd (usually         with root privilege).          Do not enable UseLogin on your machines or disable UseLogin         again in /etc/sshd_config:                 UseLogin no  We also have received many reports about attacks against the crc32 bug.  This bug has been fixed about 12 months ago in OpenSSH 2.3.0. However, these attacks cause non-vulnerable daemons to chew a lot of cpu since the crc32 attack sends a tremendously large amount of data which must be processed.  OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt, Kevin Steves, Damien Miller and Ben Lindstrom.    The following patch fixes the UseLogin vulnerability in OpenSSH 3.0.1 and earlier releases.  --- session.c   11 Oct 2001 13:45:21 -0000      1.108 +++ session.c   1 Dec 2001 22:14:39 -0000 @@ -875,6 +875,7 @@                 child_set_env(&env, &envsize, "TZ", getenv("TZ"));           /* Set custom environment options from RSA authentication. */ +       if (!options.use_login)         while (custom_environment) {                 struct envstring *ce = custom_environment;                 char *s = ce->s;