Russ McRee has discovered some vulnerabilities in WebCalendar, which can be exploited by malicious people to conduct cross-site scripting and request forgery attacks.

1) Input passed to the "tab" parameter in users.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

2) Input appended to the URL after day.php, month.php, and week.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

3) The application allows users to perform certain actions via HTTP requests without performing any validity checks to verify the requests. This can be exploited to e.g. delete an event, ban an IP address from posting, or change the administrative password if a logged-in administrative user visits a malicious web site.

The vulnerabilities are confirmed in version 1.2.0. Other versions may also be affected.

Solution
Update to version 1.2.5, which fixes vulnerability #1 and #2. Do not browse untrusted websites or follow untrusted links while logged in to the application.

Provided and/or discovered by
Reported by Russ McRee via Secunia.

Changelog
Further details available in Customer Area

Original Advisory
WebCalendar:
http://sourceforge.net/mailarchive/forum.php?thread_name=z2u1f9585051004090711qf8e317e5k1b4ac0470131a93a%40mail.gmail.com&forum_name=webcalendar-announce
http://webcalendar.cvs.sourceforge.net/viewvc/webcalendar/webcalendar/ChangeLog?pathrev=REL_1_2

Russ McRee:
http://holisticinfosec.org/content/view/133/45/

Deep Links
Links available in Customer Area