Setting up a Wordpress blog on another server pointing to a subdomain for security purposes

Question

I have an ecommerce site with thousands of customers registered. We wish to set up a Wordpress blog on this ecommerce domain name but wish to host the blog elsewhere for added security.

After reading what happened at Linux Mint, where an insecure blog led to file access on their entire server we hope for a more secure option by splitting where they are hosted.

Our future setup will be ecommercesite.com - Hosted on server A blog.ecommercesite.com - Hosted on server B

We will add an A record of blog.ecommercesite.com to point to server B.

Would this setup prevent any potential cross site vulnerabilities should the blog side get hacked?

Answer 1

I'm trying to piece together what you are asking, but it seems to me that you want two web servers (not just virtual hosts), serving different content, both pointed to by names under the same second-level domain name (such as example.com).

That is,

• www.example.com points to one server that runs your main ecommerce site, with the web shop and all that, but nothing else
• blog.example.com points to another server that runs your blog and nothing else

You can do that. In fact, it isn't even an uncommon setup. If you broaden your horizons to Internet-wide web hosting, it is exactly what's being done all the time. Granted, most often people consolidate their own content on a single server to save on hosting costs and make things easier to manage, but there's no reason why you have to.

The security properties of such a setup, assuming that the servers do not know about each other (though you can link and reference material back and forth between them using plain web links), for each site, will be essentially identical to if you'd had only that one site and the other server didn't exist at all. In other words, someone who finds a vulnerability in your Wordpress setup will, in an ideal world, not be able to leverage that to gain access to your ecommerce site, or the other way around, any more than, say, a security problem on blogger.com allows exploiting a page on wordpress.com.

Answer 2

The risk here is that a blog site is likely to have more vulnerabilities than an e-commerce site. So hackers will attack the easier target in the hopes of getting a foothold in a server that then allows them to hop to a more secure server. This is a very common technique for attacking high-value but generally well secured systems.

Separating the services onto different physical hosts - perhaps on completely different networks but at least in different DMZ's is simple good practice. You are reducing the risks.

However, you still need to ensure that there are no possible back-end links between the 2 servers.

Remember that your protection here is in two forms. Firstly the direct protection of the web site, the web server and the physical server. Secondly any possible way for someone who has managed to gain access (remote command line or malware) to one server gaining access to another.

You may not always have control over all aspects of the first due to the use of 3rd party software but you certainly should have control over the second.

Note that if your e-commerce service offers credit-card payments, you will be bound by the Payment Card Industry Data Security Standard (PCI DSS). Part of the requirements for that is segregation of card/customer data from other forms of data.