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Security Advisory                                                       CERT-NL
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Author/Source : CERT-NL (Erik-Jan Bos)                      Index  :    S-93-11
Distribution  : World                                       Page   :          1
Classification: External                                    Version:      Final
Subject       : wuarchive ftpd Vulnerability                Date   :  11-Apr-93
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CERT-NL received information from CERT Coordination Center who has
received information concerning a vulnerability in versions of
wuarchive ftpd available before April 8, 1993. Vulnerable wuarchive
ftpd versions were available from
wuarchive.wustl.edu:/packages/ftpd.wuarchive.shar and many other
anonymous FTP sites.

We strongly recommend that any site using versions of wuarchive ftpd 
dating prior to April 8, 1993, immediately take corrective action or 
remove this service.

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I.   Description

     A vulnerability exists in the access control mechanism in this 
     version of ftpd.

     
II.  Impact

     Anyone (remote or local) can potentially gain access to any 
     account including root on a host running this version of ftpd.


III. Solution 

     Affected sites may choose to disable anonymous FTP service until
     they have corrected this problem.
        
     Affected sites can correct this problem through one of the
     following two procedures:

     A. A new version of ftpd has been released that provides new features
        and also fixes this security problem.  Sites can obtain this new 
        version via anonymous FTP from wuarchive.wustl.edu (128.252.135.4). 
        The files are located in:

                                                      Size      Checksum
        /packages/wuarchive-ftpd/wu-ftpd-2.0.shar    421953      08786
        /packages/wuarchive-ftpd/wu-ftpd-2.0.tar     491520      27466

     B. Make modifications to your existing wuarchive ftpd sources using
        the diff output provided below, recompile and install according to 
        the instructions provided. 

*** ftpd.c.orig
--- ftpd.c
***************
*** 413,418 ****
--- 413,420 ----
                end_login();
        }
  
+       anonymous = 0;
+ 
        if (!strcasecmp(name, "ftp") || !strcasecmp(name, "anonymous")) {
                if (checkuser("ftp") || checkuser("anonymous")) {
                        reply(530, "User %s access denied.", name);

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The CERT Coordination Center wishes to thank Scott Paisley, Computer Systems 
Support Manager, Factory Automated Systems Division, N.I.S.T., for informing 
us of this vulnerability.  We would also like to thank Chris Myers, Washington
University, for his quick response to this problem.

CERT-NL wishes to thank CERT Coordination Center for bringing the
information regarding this vulnerability to our attention.

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==============================================================================
CERT-NL is the Computer Emergency Response Team, located in The
Netherlands. CERT-NL is a Full Member of the Forum of Incident Response
and Security Teams (FIRST). The constituency of CERT-NL are the SURFnet
connected institutions.

Past CERT-NL Security Bulletins and other CERT-NL related material can
be found on the anonymous FTP server of SURFnet bv:
"ftp.nic.surfnet.nl" [192.87.46.3], in the directory "netman/cert-nl".
This information is also available using email. Send an email saying
"help" to "mailserv@nic.surfnet.nl".

In case of computer or network security problems please contact CERT-NL
or the CERT of your own constituency. Please be aware of the fact that
we are are one hour ahead of Universal Time Coordinated (i.e. UTC+0100).
Email:     cert-nl@surfnet.nl
Phone:     +31 30 310290
Fax:       +31 30 340903
Snailmail: SURFnet bv
           Attn. CERT-NL
           P.O. Box 19035
           NL - 3501 DA  UTRECHT
           The Netherlands
A 7*24h phonenumber is available to SURFnet SSC's and FIRST members on request
==============================================================================

--- End of Advisory

__
 
Erik-Jan.