squirrelmail/doc/security.txt

Securing Your SquirrelMail Setup
--------------------------------

We try to make SquirrelMail as secure as possible, but the security of
an install depends on a lot of factors. This file lists some tips to
further improve the security of your webmail system.

- PHP configuration. It's very important to turn register_globals OFF.
  The majority of security issues discovered in SquirrelMail in the past
  could only be exploited when register_globals was set to on. If you
  need register_globals for other web applications, turn it on specifically
  for those apps.

- HTTPS/SSL Logins. SquirrelMail runs fine over an https / SSL connection,
  and it's not that hard to set one up.

- Data dir / attachment dir. Make sure that you've set these up with the
  right permissions (only for the webserver user) and that they're outside
  of your webserver's document root. See INSTALL for details.

- IMAPS / TLS. If your IMAP server is not on the same host as SquirrelMail,
  you can configure SquirrelMail to use an encrypted connection to your
  IMAP server. Note that this makes no sense if both are on the same machine.
  See doc/authentication.txt for info.

- config.php. Some options in conf.pl / config.php allow for passwords to
  be set in that file, e.g. the addressbook/preferences DSN, and LDAP
  addressbooks. When setting a sensitive password, check that config.php
  is not readable for untrusted system users, and consider the possibility
  of it being read by other users of the same webserver.

- Subscribe to the squirrelmail-announce mailinglist to be informed about new
  releases which may fix security bugs. If you run SquirrelMail packaged by
  your distribution, make sure to apply their security upgrades.

- If you use SELinux, SquirrelMail will not work unless you create a policy
  for it. In the SELinux Policy Editor, under HTTPD Service, enable
  "allow HTTPD scripts and modules to connect to the network".

These are only some tips to get you started. A truly secure system needs
careful tweaking of all components, including PHP, Apache, mailserver,
the underlying OS, which users can login, etc. Searching the web will turn
up lots of information.


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