.ico Malware

So, this is a hopefully, because it’s been a bit since I have done this, and things seem to be clean. So, there is a reasonably common bit of Malware out there that seems to affect WordPress sites, I say reasonably common, because in my time looking for a solution, I have come across a fair number of others with the issue, but no solutions. And I have tries several solutions. As of now, I have been a few months clean, and without hacky work-arounds. I’m going to attempt to run through what I did that held it at bay, and what seems to have finally managed to purge it, in hopes of helping others.

The Malware itself basically would occasionally redirect the blog domain to a spam website. I say occasionally, because it’s not all the time, and with enough anti-advertising stuff in your browser, you may never see it happen. I have personally, never once seen it happen, on any of the sites I run on this web space. I first found it was infected because occasionally, my wife would mention that someone she had linked her blog to, was getting sent to a spam website. Initially I thought maybe someone was mistyping the domain along the line. My wife also said it would happen occasionally. In my work combating this malware, it seems like the actual redirect occurs slowly over time, as the infections spreads.

It also will spread across sites hosted on the same server. Which made it extra tricky to fight because I had to juggle several sites at once.

Part 1 – Keeping It at Bay and How it Spreads

I have no idea how the infection was initially started, which is rough, because that would be key to KNOWING it’s gone. As near as I can tell, the initial source of the infection is int he uploads directory of a blog. It eventually starts to add “gibberish code” to files like wp-config.php and settings.php. I say “Gibberish Code” because it’s actual PHP, but it’s very messy in it’s design and encoding to make it hard to read to locate files. The gibberish code would generally show up at the top of the files, but could be elsewhere.

Eventually, random folders would start showing up in the root WordPress directory, sometimes with gibberish names, sometimes with specific spammy sounding names, sometimes with names that appear to be part of the blog (like ‘site’ or ‘blog’).

The first step in holding this at bay was so dump all write permissions for several critical WordPress files that kept being infected. This seemed to only sort of help, the problem was more that the owner, www-data, still could write to the files.

The next step was to convert all of the web files to an alternative user account as the owner, then set the files so www-data could only read. This created a new problem, it meant I could not easily update anything or upload images for blog posts easily. Since www-data had no permissions to write anywhere. If I was making a new post, I would have to SSH into the server, temporarily change the permissions, then change things back.

Pain in the ass.

My temporary fix there, was to keep the current year as writable, and run a script that would probe for malware files and delete them. There were two scripts, one for the hidden .ico files that would crop up and one for any .php files that were in the Uploads folders. Both run with a cron job.

#!bin/sh
/usr/bin/find /var/www/html -name ".*.ico" -exec rm {} +

This is, admittedly, an EXTREMELY Hack way to correct this problem. Hack less in the sense of “computer hacker”, hack in the sense of “jankey or shoddy”. But it worked, while I figured out the root issues.

Part 2 – Fixing the Issue

Eventually I sat down and just sort of rebooted everything, all at once. I started with everything set up as an alternative user permissions and locked down. I then scrubbed out all infected php and ico files from the upload folders. I then thoroughly scrubbed out the wp-config files. Basically, any files I would need to moved to a fresh WordPress install, which was the uploaded images, and the configurations, were completely sanitized.

Next, I downloaded a fresh copy of WordPress, expanded it out and made copies for each site folder with websitename_new. After that, I copied the uploads folders and wp-config files to the new copies. Then i renamed each current folder as websitename_old, and renamed the new ones as simply websitename. (I actually did this and the subsequent steps once at a time for each site). This made the new, fresh installed copies live.

Except they have no plug ins and no themes. I did not transfer any old theme files or plug in files, for worry of infection. Instead I went into the old folders to get a list, then redownloaded each theme and plug in to the fresh copies. This meant doing some reconfiguring but it was worth it for clean copies. I also left out anything that wasn’t absolutely essential to the basic look and operation.

Site note, when a fresh install copy is made live, it may not load until you go into /wp-admin, and change the theme to literally anything else (Generally, the current year WordPress Default works). The config files will still be looking for the non-existent old theme.

With everything fresh and ready to go, I deleted the old potentially infected copies, to ensure the infection was now completely purged. After that, I created a backup folder, and copied all of the current fresh versions of the site folders to the back ups. This way, in the event of a reinfection, I could simply, slap a fresh back up in place easily. It might be missing a few recent images, but it would be way less work.

Still worried, I then reverted the permissions for the sites back to www-data, but I did them one at a time, roughly a week apart. Carefuly checking for reinfection with each change.

So far so good, I have not had any problems. Here is hoping it stays.