rsync security advisory (fwd)

From: Andrea Barisani (lcars_at_gentoo.org)
Date: 12/04/03

  • Next message: Trustix Security Advisor: "TSLSA-2003-0048 - rsync" 
    Date: Thu, 4 Dec 2003 14:59:40 +0100
To: bugtraq@securityfocus.com

    ----- Forwarded message from rsync-announce@lists.samba.org -----

    Date: Thu, 4 Dec 2003 16:55:27 +1100
    To: rsync-announce@lists.samba.org, rsync@lists.samba.org
    Mail-Followup-To: rsync-announce@lists.samba.org, rsync@lists.samba.org
    Cc:
    From: rsync-announce@lists.samba.org
    Subject: [rsync-announce] rsync security advisory

    rsync 2.5.6 security advisory
    -----------------------------

    December 4th 2003

    Background
    ----------

    The rsync team has received evidence that a vulnerability in rsync was
    recently used in combination with a Linux kernel vulnerability to
    compromise the security of a public rsync server. While the forensic
    evidence we have is incomplete, we have pieced together the most
    likely way that this attack was conducted and we are releasing this
    advisory as a result of our investigations to date.

    Our conclusions are that:

     - rsync version 2.5.6 contains a heap overflow vulnerability that can
       be used to remotely run arbitrary code.

     - While this heap overflow vulnerability could not be used by itself
       to obtain root access on a rsync server, it could be used in
       combination with the recently announced brk vulnerability in the
       Linux kernel to produce a full remote compromise.

     - The server that was compromised was using a non-default rsyncd.conf
       option "use chroot = no". The use of this option made the attack on
       the compromised server considerably easier. A successful attack is
       almost certainly still possible without this option, but it would
       be much more difficult.

    Please note that this vulnerability only affects the use of rsync as a
    "rsync server". To see if you are running a rsync server you should
    use the netstat command to see if you are listening on TCP port
    873. If you are not listening on TCP port 873 then you are not running
    a rsync server.

    New rsync release
    -----------------

    In response we have released a new version of rsync, version
    2.5.7. This is based on the current stable 2.5.6 release with only the
    changes necessary to prevent this heap overflow vulnerability. There
    are no new features in this release.

    We recommend that anyone running a rsync server take the following
    steps:

       1) update to rsync version 2.5.7 immediately

       2) if you are running a Linux kernel prior to version 2.4.23 then
          you should upgrade your kernel immediately. Note that some
          distribution vendors may have patched versions of the 2.4.x
          series kernel that fix the brk vulnerability in versions before
          2.4.23. Check with your vendor security site to ensure that you
          are not vulnerable to the brk problem.

       3) review your /etc/rsyncd.conf configuration file. If you are
          using the option "use chroot = no" then remove that line or
          change it to "use chroot = yes". If you find that you need that
          option for your rsync service then you should disable your rsync
          service until you have discussed a workaround with the rsync
          maintainers on the rsync mailing list. The disabling of the
          chroot option should not be needed for any normal rsync server.

    The patches and full source for rsync version 2.5.7 are available from
    http://rsync.samba.org/ and mirror sites. We expect that vendors will
    produce updated packages for their distributions shortly.

    Credits
    -------

    The rsync team would like to thank the following individuals for their
    assistance in investigating this vulnerability and producing this
    response:

       * Timo Sirainen <tss iki.fi>

       * Mike Warfield <mhw wittsend.com>

       * Paul Russell <rusty samba.org>

       * Andrea Barisani <lcars gentoo.org>
       
    Regards,

    The rsync team

    _______________________________________________
    rsync-announce mailing list
    rsync-announce@lists.samba.org
    http://lists.samba.org/mailman/listinfo/rsync-announce

    ----- End forwarded message -----

  • Next message: Trustix Security Advisor: "TSLSA-2003-0048 - rsync"

    Relevant Pages