The published exploit for WordPress 3.0.4 isn’t accurate
We were informed yesterday of a published vulnerability for WordPress 3.0.4, “Stored XSS (via Editor role)”.
This is an invalid report. (Edit: The exploit has been delisted by the database.)
The dead giveaway was the title: “via Editor role.” In WordPress, users with the role of Editor or Administrator have the ability to post unfiltered HTML. It has always been like this.
From the Security FAQ on the Codex:
Users with Administrator or Editor privileges are allowed to publish unfiltered HTML in post titles and content. WordPress is, after all, a publishing tool, and people need to be able to include whatever markup they need to communicate. Users with lesser privileges are not allowed to post unfiltered content.
We also issue a warning for security researchers, which wasn’t followed here:
If you are running security tests against WordPress, use a lesser privileged user so that all content is filtered.
How to change this behavior
In multisite, only super administrators can publish unfiltered HTML. All other users are considered untrusted in this case, as they can be administrators for their own sites. (There is a plugin to restore unfiltered HTML to editors and regular administrators in this case, if you trust those users: Unfiltered MU.)
There’s a constant you can use to disallow unfiltered HTML for everyone, including administrators and super administrators. To disallow unfiltered HTML for all users, you can add this to wp-config.php:
define( 'DISALLOW_UNFILTERED_HTML', true );
Filtered HTML for Editors
To deny unfiltered HTML for Editors, try the Filtered HTML for Editors plugin, which I put together today. The description and FAQ go into much of what was covered here.
How to report security vulnerabilities
Standard practice when finding a security vulnerability is to privately notify the vendor and give them an opportunity to respond and prepare a fix for public release. It’s the concept of responsible disclosure. We’ll always credit responsible disclosure in the release announcement as the person requests, such as with a link to your blog.
For WordPress, suspected vulnerabilities can be privately emailed to our security team at security@wordpress.org.
Unfortunately, not everyone follows responsible disclosure. In the case of 3.0.4, an exploit published regarding 3.0.3 forced our hand to release the fix we had been privately testing (thanks to responsible disclosure). This can sometimes force our hand in very bad ways — the fixes included in 3.0.4 were very complicated and involved more than a hundred hours of work from more than a dozen individuals. Had we rushed a release due to a public announcement, we might have missed something.
Not following responsible disclosure also prevents us from responding to invalid reports. Unfiltered HTML results in false reports every so often. The fact that this was published as an exploit, without any confirmation or notification, only contributes to FUD and perception issues.
The status of WordPress 3.0.4
This all said, there are currently no known vulnerabilities for WordPress 3.0.4. I’ll go knock on wood now.
Travis Miller, 
pexysedinny are discussing. 
Valentinas and 8 others are discussing. 
Andrew Nacin 9:48 pm on December 31, 2010 Permalink |
The report is being removed from the exploit DB. I’ve updated the post.
Travis Miller 4:15 pm on January 3, 2011 Permalink |
Hi Andrew -
Thanks for the update. I’ve been trying to research this security patch, and a few things still aren’t clear.
1. Do I need to upgrade my 3.x sites to 3.0.4, or not? This post seems to be saying that the vulnerability that 3.0.4 supposedly fixes did not exist in the first place. Am I understanding that correctly?
2. If there *is* a vulnerability, does it exist in the 2.x branch as well, or only 3.x?
3. If the vulnerability does exist in 2.x, is there an official or quasi-official patch for that branch, or am I stuck doing a major version upgrade from 2.x to 3.x?
Sorry if this isn’t the best venue for this question – comments are closed on the post on the main WordPress blog, so I can’t ask there. I’m sure others in the WordPress community would appreciate some clarification on these questions.
Jane Wells 4:31 pm on January 3, 2011 Permalink |
Hi Travis. I think you misunderstood Andrew’s post. After 3.0.4 came out, a website started reporting that there was a new vulnerability. That is the one that is invalid. Yes, you should update to 3.0.4. The 2.x versions are no longer supported, so please please update to the most current version. If you are still running 2.x versions, you are likely facing multiple vulnerabilities.
Travis Miller 6:58 pm on January 3, 2011 Permalink |
Thanks, Jane. You’re correct; I misunderstood the post. Thanks for the info.