A couple of weeks ago Adam Warner suggested we have do a security comparison between WordPress and WordPress MU. In particular, he was interested to know which was more likely to pass PCI accreditation.
I contacted Doncha, lead developer of WordPress MU for some feedback. Interestingly, we both shared similar sentiments and it made this question fairly simple to address.
As WordPress MU shares most of the same code as WordPress, there were only three points I wanted to raise:
So to summarise: I feel WordPress by default may be a better option for PCI accreditation. It encourages a seperation mentality. Seperate blog, seperate database etc; However, from a realistic risk analyses, they are more or less the same in my opinion.
bro, i can only imagine creating a separate DB for 100,000+ blogs. plugins would all have to be rewritten.
I can imagine 100,000 bloggers knocking at my door when every single one of them have been hacked because one plugin that one blog used shared the same database.
But even if you use multiple dbs, the username and passwords used to access them has to be stored somewhere. If someone exploits your server then all bets are off and he gets access to everything..
Donncha, it really depends on the vulnerability in question. Database separation is more for input validation type vulnerabilities, such as SQL Injection.
By having the data and users separated, we can now focus on database and database user permissions and security.
However, all previous comments (including mine) are actually irrelevant.
The scope of the original question was PCI compliance. From a security threat model, a shared database scheme and setup of WP MU hosting critical information shared with other non-critical data stores is really not the way forward.
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