EnGarde Secure Linux Security Advisory: stunnel

+------------------------------------------------------------------------+
| EnGarde Secure Linux Security Advisory               December 27, 2001 |
| http://www.engardelinux.org/                           ESA-20011227-01 |
|                                                                        |
| Package:  stunnel                                                      |
| Summary:  There is a format string vulnerability in stunnel.           |
+------------------------------------------------------------------------+

  EnGarde Secure Linux is a secure distribution of Linux that features
  improved access control, host and network intrusion detection, Web
  based secure remote management, complete e-commerce using AllCommerce,
  and integrated open source security tools.


OVERVIEW
- --------
  There is a format string vulnerability in stunnel which may allow an
  attacker to exploit a victim by impersonating a mail server.


DETAIL
- ------
  There are a couple of instances in stunnel where a format is not passed
  to a printf-like function, leading to your classic format string
  vulnerability.  It is not know weather or not it is exploitable at this
  time but all users are recommended to upgrade in any event.

  This vulnerability was disclosed on December 18 by Matthias Lange on
  the stunnel-users mailing list.  The original message may be found here:

    http://marc.theaimsgroup.com/?l=stunnel-users&m=100868569203440&w=3

  All users should upgrade to the most recent version, as outlined in


SOLUTION
- --------
  All users should upgrade to the most recent version as outlined in
  this advisory.  All updates may be found at:

    ftp://ftp.engardelinux.org/pub/engarde/stable/updates/
    http://ftp.engardelinux.org/pub/engarde/stable/updates/

  Before upgrading the package, the machine must either:

    a) be booted into a "standard" kernel; or
    b) have LIDS disabled.

  To disable LIDS, execute the command:

    # /sbin/lidsadm -S -- -LIDS_GLOBAL

  To install the updated package, execute the command:

    # rpm -Uvh <filename>

  You must now update the LIDS configuration by executing the command:

    # /usr/sbin/config_lids.pl

  To re-enable LIDS (if it was disabled), execute the command:

    # /sbin/lidsadm -S -- +LIDS_GLOBAL

  To verify the signatures of the updated packages, execute the command:

    # rpm -Kv <filename>


UPDATED PACKAGES
- ----------------
  These updated packages are for EnGarde Secure Linux 1.0.1 (Finestra).

  Source Packages:

    SRPMS/stunnel-3.22-1.0.4.src.rpm
      MD5 Sum:  e408662d6fc54f3979642c9e8c110ba4

  Binary Packages:

    i386/stunnel-3.22-1.0.4.i386.rpm
      MD5 Sum:  482ff9210541d73b114404ccb9732cf0

    i686/stunnel-3.22-1.0.4.i686.rpm
      MD5 Sum:  afad91053b8d482e36e85251fab06755


REFERENCES
- ----------

  Guardian Digital's public key:
    http://ftp.engardelinux.org/pub/engarde/ENGARDE-GPG-KEY

  Credit for the discovery of this bug goes to:
    Matthias Lange ml@netuse.de

  stunnel's Official Web Site:
    http://stunnel.mirt.net/

  Security Contact:    security@guardiandigital.com
  EnGarde Advisories:  http://www.engardelinux.org/advisories.html

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$Id: ESA-2001122701-stunnel,v 1.2 2001/12/27 16:02:00 rwm Exp $
- --------------------------------------------------------------------------
Author: Ryan W. Maple, ryan@guardiandigital.com
Copyright 2001, Guardian Digital, Inc.