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Caldera Security Advisory SA-1997.31: Additional Vulnerabilities in wu-ftpd

Original report date:  11-Dec-1997
RPM build date:    12-Dec-1997
Advisory issue date:  16-Dec-1997

Topic: Additional Vulnerabilities in wu-ftpd 2.4.2 beta 15


I. Problem Description

  This document summarizes additional vulnerabilities in the
  wu-ftpd 2.4.2 beta 15 FTP server not covered by CERT Advisory
  CA-97.27 - "FTP_bounce".  The list of affected platforms may not
  be limited to systems running under Linux.


II. Impact

  Under certain circumstances wu-ftpd 2.4.2 beta 15 allows a remote
  user to open a connection to any service on a server running the
  vulnerable version of wu-ftpd.  Under Linux, the connection will be
  established via the loopback interface which could bypass access
  controls that assume that connections can be established only via
  Ethernet, PPP or SLIP interfaces.  Other types of exploits are
  possible.

  This problem was present on the following OpenLinux releases:

    Base 1.0
    Lite 1.1
    Base 1.1
    Standard 1.1

  To determine if you are affected and need this update execute the
  following:

    rpm -q wu-ftpd

  If the results show wu-ftpd-2.4.2b15-4 or earlier then you will need
  to update.

  NOTE: The problem described in CERT Advisory CA-97.27 suggests
  using wu-ftpd 2.4.2 beta 15.  Versions of OpenLinux prior to 1.2
  included wu-ftpd release 2.4.2 beta 13 or earlier.  However,
  this should not be a problem if Caldera Security Advisory
  SA-1997.27 has already been applied since it recommends that
  wu-ftpd-2.4.2b15-4 be installed.  But the version of wu-ftpd 2.4.2
  beta 15 described in this document (wu-ftpd-2.4.2b15-5) contains
  *additional* security fixes.


III. Solution

  The proper solution is to install the new wu-ftpd package.
  This package is located on Caldera's FTP server (ftp.caldera.com):

  The binary RPM can be obtained at:
  ftp://ftp.caldera.com/pub/openlinux/updates/1.1/current/RPMS

  The source RPM can be obtained at:
  ftp://ftp.caldera.com/pub/openlinux/updates/1.1/current/SRPMS

  All that is required to do to install the fix is the following:

    rpm -U wu-ftpd-2.4.2b15-5.i386.rpm

  The MD5 checksums (from the "md5sum" command) for these packages are:

  1ce8038acc06eb200e87f2c8024df633  wu-ftpd-2.4.2b15-5.i386.rpm
  e81777eae4b6631fd3a9a238bd5da0be  wu-ftpd-2.4.2b15-5.src.rpm


IV. References / Credits

  This vulnerability was discovered and fixed by Olaf Kirch (email:
  okir@caldera.de).  Other Linux vendors and CERT have been apprised
  of this vulnerability.  Time is being given to other vendors
  to release their fixes before more details will be published.
  According to its maintainer, Stan Barber, release wu-ftpd 2.4.2
  Beta 16 is expected on or before 25-Dec-1997.

  The CERT Coordination Center is located at:

    http://www.cert.org

  CERT Advisory CA-97.27: "FTP Bounce" (10-Dec-1997):

    http://www.cert.org/pub/advisories/1997/CA-97.27.FTP_bounce.html

  CERT Tech Tip "Problems With The FTP PORT Command" (10-Dec-1997):

    ftp://ftp.cert.org/pub/tech_tips/FTP_PORT_attacks
  
  White Paper: "The FTP Bounce Attack" (12-Jul-1995):

    ftp://avian.org/random/ftp-attack

  Caldera Security Advisory SA-1997.27: "Vulnerability in wu-ftpd":

    http://www.caldera.com/tech-ref/security/SA-1997.27.html

  This advisory and other Caldera security resources are located at:

    http://www.caldera.com/tech-ref/security/

  This Security Alert closes Caldera internal problem report #1361.


V. PGP Signature

  This message was signed with the PGP key for security@caldera.com.

  This key can be obtained from:
    ftp://ftp.caldera.com/pub/pgp-keys/

  Or on an OpenLinux CDROM under:
    /OpenLinux/pgp-keys/

  $Id: SA-1997.31,v 1.2 1997/12/16 06:09:27 ron Exp $

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