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    • New note by bobjonkman 2 April 2020
      oh, hang on. That was a ReTweet from @wilkieii@twitter.com But you're still invited to make that presentation!
    • New note by bobjonkman 2 April 2020
      ...and you'll make a presentation at an upcoming @KWLUG meeting, right? On the very platform you're presenting about!
    • bobjonkman repeated a notice by hubert 2 April 2020
      RT @hubert ♲ @matrix: RT @wilkieii@twitter.com Successfully using entirely self-hosted+federated Riot/Matrix/Jitsi/Etherpad/PeerTube to host lectures, teleconference with students, answer questions in chat, and collaboratively edit their code. Write-up is incoming. Once I take a nap. 🐦🔗: twitter.com/wilkieii/status/12…
    • Favorite 2 April 2020
      bobjonkman favorited something by hubert: ♲ @matrix@mastodon.matrix.org: RT @wilkieii@twitter.comSuccessfully using entirely self-hosted+federated Riot/Matrix/Jitsi/Etherpad/PeerTube to host lectures, teleconference with students, answer questions in chat, and collaboratively edit their code. Write-up is incoming. Once I take a nap.🐦🔗: twitter.com/wilkieii/status/12…
    • New note by bobjonkman 22 March 2020
      He'll never find it again. But you get a tree!
    • New note by bobjonkman 22 March 2020
      Ja, ich bin hier noch. Aber meine timeline ist oft zwei oder drei monaten langzam...
    • Favorite 27 February 2020
      bobjonkman favorited something by showerpickles: imagine an internet that was ran like a utility. one where it was the norm to run a little box server at your home that you run your services on (email, mastodon, file storage, etc), and there was a whole industry of unionized repair people who would come to your […]
    • Favorite 27 February 2020
      bobjonkman favorited something by douginamug: One of the core 'demands' of #ExtinctionRebellion is to set up a #CitizensAssembly. This is not a new concept: #sortition has been around since Athens.I find a lot of people worried about trusting 'normal people' to make big decisions. I would love to have a CA as one of the […]
    • bobjonkman repeated a notice by douginamug 27 February 2020
      RT @douginamug #ExtinctionRebellion session @ #35c3 is FULL! One third of the people sitting on the floor 😂 Amazing to see a room full of hackers excited to join the cause. There's enthusiasm to help non-techy people switch to #signal, #mastodon & #nextcloud ⚡ 💻 🌐
    • Favorite 27 February 2020
      bobjonkman favorited something by douginamug: #ExtinctionRebellion session @ #35c3 is FULL! One third of the people sitting on the floor 😂 Amazing to see a room full of hackers excited to join the cause. There's enthusiasm to help non-techy people switch to #signal, #mastodon & #nextcloud ⚡ 💻 🌐

Recovering from a WordPress hack

Posted by Bob Jonkman on October 29th, 2013

WordPress logo cleaved by axe

WordPress Hacked!

Last Friday I was finally getting around to upgrading the WordPress installations on the SOBAC server from v3.6 to v3.6.1. Surprise! WordPress v3.7 had just been released the night before!

WordPress upgrades are famous for their ease of installation. Surprise! After upgrading the first installation most of the plugins were missing, and the theme was broken. A quick look at a directory listing showed that the plugins and themes were still installed. A quick look with a text editor showed some peculiar PHP code at the top of every .php file in the plugins folders. Surprise! This WordPress installation had been hacked! Fortunately, of the five instances of WordPress on this server, only two appeared to be affected. This Blog Is Not For Reading was not one of them.

Each .php file started with something like this:

<?php $zend_framework="\x63\162\x65(…)\x6e"; 
@error_reporting(0); 
zend_framework("", "\x7d\7(…)

Injected, obfuscated PHP code at the top of every .php file, referencing the zend_framework

Searching the Internet for “wordpress plugin invalid header zend_framework” I found a reference that makes me think this may have been possible because of a flaw in an earlier version of the WordPress code that handles comments. Most likely one of the comment fields (user name, e-mail, web address or the comment text itself) wasn’t properly sanitized, and allowed some kind of code injection (probably PHP injection, not a MySQL injection; the contents of the databases appeared to be untouched).

From the backups of the server it appeared that the breach occurred in or before August — either just before the release of WordPress 3.6 on 1 August 2013 or just before the release of WordPress 3.6.1 on 11 September 2013. If I had not been slack in upgrading to WP v3.6.1 then this breach might have been identified much sooner.

The upgrade to WordPress identified the modified files because the injected code preceded (and corrupted) the WP headers, and so WP v3.7 disabled any affected plugins and themes.

The Fix Is In

I renamed the directory containing the WordPress code, installed a fresh copy of WP3.7, cleaned and copied the wp-config.php and .htaccess files, uploaded a small image to create the wp-content/uploads hierarchy, then copied the upload folder (which didn’t contain any .php files), and then re-installed and re-configured the themes and plugins directly from the WordPress site.

Aside from the additional PHP code, there didn’t appear to be any other damage to the system. So I used the original wp-config.php (but cleaned, and with the “Authentication Unique Keys and Salts” section refreshed), and the new installation just used the existing databases. If there’s any malcode in the databases then that could re-infect the system, so I’m keeping an eye on it.

I have no idea what the malcode was intended to do. It didn’t corrupt the databases or anything else, but it’s possible it was acting as a keylogger or phoning home some other way. If I feel inclined I might try to de-obfuscate the injected code, but right now I don’t really feel like doing forensics.

Someone suggested using AppArmor to make the WordPress directories read-only. I’m not sure that locking down the WP directory is a good idea. The big new feature in WordPress 3.7 is its automatic update feature. If the WordPress directories are locked down then future security updates won’t be applied automatically. If there is an exploit and WordPress issues a new release to fix it, then a locked-down site will experience a delay in upgrading until the SysAdmin notices and upgrades manually (which is what used to happen before v3.7, but it seems a bad idea to delay upgrades when that’s no longer necessary). Also, the plugin and themes directories would be locked down, and they still require fairly frequent manual upgrades.

I sent the users on the affected sites this message:

While doing upgrades on WordPress yesterday I saw that your blog had been hacked sometime during or before August. I’ve fixed it (re-installed the code, copied your media library, re-installed themes and plugins). I don’t think any damage was done beyond the insertion of malicious code in some of the WordPress files. I don’t know what the action of that code was intended to be, but you should change your WordPress password just in case the bad guys captured it. You can change your password on the “Users, Your Profile page” once you’ve logged in.

After spending some time on Saturday fixing the two hacked WordPress sites I’m a little paranoid, and making sure to implement updates quickly. But a little paranoia is good — it’ll ensure I won’t become complacent again.

–Bob.

WordPress Hacks by Rafael Poveda is used under a CC BY-NC-SACreative Commons — Attribution-NonCommercial-ShareAlike — CC BY-NC-SA license.

 
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