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ARCHIVE: Zardoz 'Security Digest' - Archives (1989 - 1991)
DOCUMENT: Zardoz 'Security Digest' V3 #11 1991-08-06 (1 file, 1017 bytes)
SOURCE: http://securitydigest.org/exec/display?f=zardoz/archive/311.txt&t=text/plain
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Date: Tue Aug 6 22:30:48 PDT 1991
Subject: Security Digest V3 #11

Security Digest Volume 3 Issue 11

subject(s):

            anonymous ftp misconfigurations

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DO NOT PUT ANY LIST CONTENTS IN LOCATIONS ACCESSABLE TO NON-MEMBERS.
If you must keep copies on-line, please encrypt them at the very least.

PLEASE POST TO:                              security@uninet.cpd.com
PLEASE SEND EMERGENCY ALERTS TO:   security-emergency@uninet.cpd.com
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Postings that describe security holes/fixes have a * in their subject.


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Date: Tue, 06 Aug 91 15:05:12 EDT
From: "Kannan Varadhan" <kannan@oar.net>
Subject: anonymous ftp misconfigurations

Recently, we found some miscreants had placed a few megatons of garbage
in one of our anonymous ftp repository machines.  We then found that
the anonymous ftp directories were writeable by the user `ftp', which
is the userid used for anonymous ftp.  There may be a few people out there
who have made the same mistake.  Hence this short note on the topic.

To find if you have the problem, you can

        a) Check if your anonymous ftp directories are owned by ftp,
        and writeable,
or      b) do an anonymous ftp to the machine, and attempt to
        put the file in one of the directories or surdirectories,
or      c) do `find ~ftp -perm -0200 -user ftp -ls'.

The last option is preferable for it recursively lists all files and
directories that are tamperable.

To fix this, you would use `chown -R daemon.daemon ~ftp', or "find"
once more.

The user daemon seems safest, as one does not use it as a login id for
any purpose at all.  You could choose any that you prefer.

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        End of Security Digest Volume 3 Issue 11
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