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20080407 Monday April 07, 2008

The WordPress Security Cancer

The blogosphere has had its share of maladies before. Comment spam, trackback spam, splogs and link trading schemes are the colds and flus that we've come to know and groan about. But lately, a cancer has afflicted the ecosystem that has led us at Technorati to take some drastic measures. Thousands of WordPress installations out in the wilds of the web are vulnerable to security compromises, they are being actively exploited and we're not going to index them until they're fixed.

We know about them at Technorati because part of what we do is count links. Compromised blogs have been coming to our attention because they have unusually high outbound links to spam destinations. The blog authors are usually unaware that they've been p0wned because the links are hidden with style attributes to obscure their visibility. Some bloggers only find out when they've been dropped by Google, this WordPress user wrote

My 2.2 installation was being hacked into and spam hidden links dumped into index.php. I didn't notice until google decided to ban me (they have now reincluded my site).
read it

To their credit, the WordPress developers have been fixing the issues. They released v2.3.3 in February and patches for older releases to thwart this exploit. More recently, they released v2.5, which in addition to having the flawed XML-RPC code fixed, boasts a number of new features. But from what I can tell, despite brisk uptake many blogs remain obliviously vulnerable and the occurrence of compromised blogs seems to only be accelerating. As of today, here is the count of blogs running WordPress installs that have pinged Technorati in the last 90 days:

VersionCount (in thousands)
and it trails off with more point releases. So 2.3.3 and 2.5 have enjoyed rapid adoption but AFAICT, it ain't rapid enough -- there are still hundreds of thousands of vulnerable installations out there. Note: I didn't include the WordPress/MU installations out there, I'm note sure what, if any, vulnerabilities are on those sites and anyway, there's a long tail of splog sites running that shite already.

So at Technorati today, I posted that we deployed an update to the crawlers to abort the crawl if the blog appears to have symptoms of being compromised. We'll probably rescind this measure when the number of vulnerable installations in the distribution above looks a little better (some of the false positives I've found are patched but still have unusual metrics associated with the crawl, so they look fishy). However for the time being, these are just creating a lot of noise and instability in our systems and enough is enough. If you're running an old WordPress installation and you're not getting indexed, stop what you're doing and upgrade. Just Do It. The docs on the WordPress site seem to cover what you need to know and the WordPress Forums should help fill in the gaps.

Digging through the lore, it looks like there have been a procession of security problems with WordPress installations:

There's the 'WP-Forum Plugin for WordPress "user" SQL Query Injection Vulnerability' advisory from French Security Incident Response Team in January.
theme distributors
WordPress theme author Derek Punsalan advised 'Do not download WordPress themes distributed by 3rd party sites' last November.

Using Technorati membership information, I have personally contacted several hundred of bloggers about this issue. These have included blogs with no authority as well as blogs belonging to A-listers. Many have been grateful for the heads up but none (that I have spotted) have posted about this issue. The blogs that are unclaimed are SOL, I don't have any way to reach them (without groping around their site to find a contact email, though I've done a little of that too). Kevin Burton has made a public plea, Anyone Want to Help Fix these Compromised Wordpress Blogs? One blog that did break the silence (Deep Jive Interests) did so in response to tweets about the issue that Kevin's been facing on TailRank.

But is outreach to bloggers going to be enough to stop the spread of this cancer? Probably not. I think the best way to get the word out is to spread the word, tell bloggers you know to post about it. For their part, what I'd really like to see from the WordPress folks (and all blog CMS developers) are

  1. Automated updates -- I understand that automating upgrades my be problematic when there are database schema changes and such required but installing security patches should be an option in the administrative console
  2. Security check services -- Bloggers who are uncertain of their blog's vulnerability should be able to authenticate (via OpenID) that they are the author and have their blog sniffed for security holes. OK, this won't work for old versions that don't support OpenID or if, heaven forbid, the OpenID libraries themselves are compromised but I think you get the point. If it can be sanely checked, check it.
Ultimately, this issue may have to be resolved by Matt Cutts or maybe the official Google blog publicizing it -- the threat of being in Google's penalty box seems to be a sure way to get people riled up. I expect they'll be lining up for chemo-therapy in short order.


( Apr 07 2008, 10:23:44 PM PDT ) Permalink


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