NAME

RT-Extension-PermissiveHTMLMail - Allows a greater range of HTML in RT, at the cost of security

RT VERSION

Works with RT 4.0 and RT 4.2.

SUMMARY

By default, RT displays HTML mail; however, due to security concerns, by default it does not allow the full range of HTML to be used. Specifically, it prevents:

Tables

Because RT cannot ensure that HTML in email is balanced, malicious email messages can use tables to mimic or mask parts of the standard RT UI. This opens RT to a broad range of "phishing attacks," wherein the user believes they are clicking a benign RT link, which actually is controlled by the originator of the email. This can allow attackers to steal passwords and compromise RT, and possibly other servers.

Many text styles

CSS is a powerful tool; it can also be used to mimic or mask parts of the standard RT UI. By default, RT thus only allows a small subset of CSS properties, which are sufficient for simple styling. Allowing arbitrary styles could lead to effective "phishing attacks," compromising passwords.

Installing this extension loosens the above restrictions; this should be sufficient for most needs. However, RT will still only allow HTML tags that it recognizes.

Installing this extension also additionally provides a $AllowDangerousHTML configuration option. Setting this alters RT from using a whitelist (allowing only HTML tags and attributes which it knows to be safe) to using a blacklist (skip tags and attributes which are unsafe). This is unsafe and dangerous, as there are guaranteedly further unsafe tags which RT does not know to prevent. Enabling this feature allows your RT account to be compromised by a malicious email. Do not enable it (via Set( $AllowDangerousHTML, 1 )) unless you understand the consequences.

INSTALLATION

perl Makefile.PL

make

make install

May need root permissions

Edit your /opt/rt4/etc/RT_SiteConfig.pm

If you are using RT 4.2 or greater, add this line:

Plugin('RT::Extension::PermissiveHTMLMail');

For RT 4.0, add this line:

Set(@Plugins, qw(RT::Extension::PermissiveHTMLMail));

or add RT::Extension::PermissiveHTMLMail to your existing @Plugins line.

Clear your mason cache

rm -rf /opt/rt4/var/mason_data/obj

Restart your webserver

AUTHOR

Best Practical Solutions, LLC <modules@bestpractical.com>

BUGS

All bugs should be reported via email to

L<bug-RT-Extension-PermissiveHTMLMail@rt.cpan.org|mailto:bug-RT-Extension-PermissiveHTMLMail@rt.cpan.org>

or via the web at

L<rt.cpan.org|http://rt.cpan.org/Public/Dist/Display.html?Name=RT-Extension-PermissiveHTMLMail>.

LICENSE AND COPYRIGHT

This software is Copyright (c) 2014 by Best Practical Solutions

This is free software, licensed under:

The GNU General Public License, Version 2, June 1991