ARCserve symlink vulnerability

[seclabs () NAI COM (NAI Labs)]

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                      Network Associates, Inc.
                        SECURITY ADVISORY
                        February 15, 2000

                  ARCserve symlink vulnerability

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SYNOPSIS

An implementation fault in the ARCserve agent script allows local
attackers to obtain root privileges and overwrite/insert data into
arbitrary files.

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VULNERABLE HOSTS

This vulnerability has been confirmed and is known to be exploitable
under Unixware 7.1.0

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TECHNICAL DETAILS

A script responsible for starting up the ARCserve agent creates
multiple world writeable statically named temp files. An attacker can
remove these files and create symlinks to other files on the system
allowing him to create root owned world writeable files or overwrite
any file on the system. It is also possible for the attacker to
insert any data he wishes to the files he overwrites due to the
nature of the configuration/tempfile system.

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COMMENTS

ARCserve agent is installed and running by default.

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RESOLUTION

SCO has developed a patch to address this issue.  More information is
available at:  http://www.sco.com/security.

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CREDITS

Discovery and documentation of this vulnerability was conducted
by Shawn Bracken at the Security Research Labs of Network Associates.

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