SA-1997.31.txt
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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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