Summary:
Sending CSRF token in GET forms is dangerous because if there are external links
on the target page then the token could leak through Referer header.
The token is not required for anything because GET forms are used only to
display data, not to perform operations.
Sending CSRF tokens to external URLs leaks the token immediately.
Please note that <form action> defaults to GET.
PhabricatorUserOAuthSettingsPanelController suffered from this problem for both
reasons.
Test Plan: Save my settings (POST form).
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, epriestley
Differential Revision: https://secure.phabricator.com/D1558
Summary:
We don't currently validate CSRF tokens on this workflow. This allows an
attacker to upload arbitrary files on the user's behalf. Although I believe the
tight list of servable mime-types means that's more or less the end of the
attack, this is still a vulnerability.
In the long term, the right solution is probably to pass CSRF tokens on all Ajax
requests in an HTTP header (or just a GET param) or something like that.
However, this endpoint is unique and this is the quickest and most direct way to
close the hole.
Test Plan:
- Drop-uploaded files to Files, Maniphest, Phriction and Differential.
- Modified CSRF vaidator to use __csrf__.'x' and verified uploads and form
submissions don't work.
Reviewers: andrewjcg, aran, jungejason, tuomaspelkonen, erling
Commenters: andrewjcg, pedram
CC: aran, epriestley, andrewjcg, pedram
Differential Revision: 758
