I’m a huge fan of iThemes Security (formerly Better WP Security). I’m such a fan, in fact, that I use it on many of my own sites as well as the WordPress sites that I manage for my current employer. But anyone that’s used iThemes Security knows that sometimes it’s does a little too good a job and you eventually run into false positives and unintended consequences.
Today I ran into such a situation. I manage 4 separate WordPress sites for distributor of industrial plumbing and HVAC components. A client who was looking for a very specific part let them know that their site was crashing when he entered it into the search bar.
That part they needed was an insert.
What do we know about the word “insert” that might explain why only that search term was causing a problem?
Could it be that iThemes is being helpful, and blocking requests to the site that look like they might be trying to write to our database?
The fact that I was seeing an Apache generated error page and WordPress wasn’t even trying to handle the request suggested that the problem happened before the request was ever passed off to the CMS. So I opened the .htaccess file for one of their sites, searched for the word insert, and found the offending lines.
Update: I’ve moved the code over to GitHub.
Basically these rules cause Apache to drop requests with suspicious data in the query string. If you look closely, one of those rules includes words like request, contact, union, declare, and insert. Deleting the offending line from the .htaccess solved the problem. I like the added protection these rules provide, so I only recommend removing them if they cause a problem. These rules try to prevent hackers from sending malicious code to your website in the first place, so if some code in your WordPress install forgets to sanitize user data, you’re still somewhat protected.
I had to remove this rule because insert is actually the name of a product the client was selling through their site and blocking this search term could affect sales. Before you remove these rules, weigh the pros and cons of your own situation.