Archive for January, 2009

Today was the CF Insider Workshop in Brussels. Line-up was the same as last week in Amsterdam, Claude Englebert from Adobe and Simon Slooten and me from Prisma IT. Mark van Hedel was supposed to join us for the ColdFusion and AJAX session, but he broke his leg last week so he couldn’t be there and Simon took over his session. The event in Amsterdam was pretty well attended with 20+ attendees, in Brussels we had a few less (but they have another event in French tomorrow). But the good news is that after years of a slumber Adobe is finally talking about ColdFusion in Europe again. Some of the attendents were even Adobe employees from other departments who wanted to know what that ColdFusion thing was about.

I have uploaded my slides from the CF Insider workshop to the Prisma IT website:

What’s new in ColdFusion 8

The ColdFusion Server Monitor

Adobe and Prisma IT are organizing the Dutch and Flemish versions of the ColdFusion Insider Workshop that is touring Europe. First we will have the Dutch one on January 22th in the Adobe office in Amsterdam and then on Januari 27th the Flemish on in Brussels. There will be speakers from Adobe and Prisma IT. Attendance is free if you get an entrance voucher by filling out the registration form.

I will be doing a presentation on the ColdFusion Server Monitor and a more general one on how ColdFusion makes life easier with all the cool new features in ColdFusion 8. If you have a good suggestion I may be persuaded to add your topic to my “OMG, nobody has questions, how do I fill the awkward silence” emergency slides.

At Prisma IT we have an application that has been under constant development for 2 years. Over that time it has seen lots of feature creep and changing requirements, and no refactoring. As you can imagine that doesn’t make for pretty code or an optimal database model. Due to a retargeting of that application and a much more focused requirements process we are finally getting ready to start reworking that application. Over the past month I have been working on and off (mostly in the train on my way to clients) on putting more structure in the long list with things we (I) really would like to change about the technology of the application. I have also been running some experiments on the code to see what the impact of certain changes would be. Amongst others this includes the experiments with changing the datatype used in MS SQL Server to store ColdFusion UUIDs.

One of the last things I wanted was to get a feel for the cost/benefit ratio of a conversion from MS SQL Server to PostgreSQL. Continue reading ‘Converting a CF application from MS SQL Server to PostgreSQL?’ »

Lately I have posted a number of posts on the state of shared hosting security. Unfortunately we have to conclude that only by taking drastic measures a hoster can begin to protect his customers from eachother. And even when the hoster locks dow everything to the best of his abilities, which disables lots of useful functionality, there are some significant holes left. Therefore I have compiled this wishlist of things I would like to see improved in Centaur to make shared hosting security a bit better and easier to deal with.


Setting up shared hosting is largely a process of trial-and-error. There is absolutely no documentation available that tells us which tags will blow up when we Sandbox the temp folder. That cfdocument will error out if the fonts folder is not allowed in the Sanbox. There is nothing to warn us that cfdump will break if we disable createObject(JAVA). What we need is better documentation and preferably a whitepaper that shows us how to configure a secure shared hosting environment step by step.

A locked down application scope

Frameworks are storing more and more data in the application scope. The application scope is currently completely unprotected: everybody can see everything. We need a way to lock down the application scope so we can only access it from just one Sandbox.

Fine grained Java permissions

The biggest useful feature we need to disable in order to protect servers is access to Java objects. We need much more control over which actions a Java class can perform before we can open up access to Java. For starters, we need knobs to disable many actions from the Runtime class. We need to be able to disable the loading of arbitrary classes by users (what is the point in disabling createObject(COM) if users can load their own version of JIntegra?), we need to stop users from killing the server with exitVM, halt etc., we need to stop them from spawning other processes etc. Then we need to have all access to SecurityPermission disabled so that users can’t simply reset the security and we need to have ReflectPermission disabled to keep our private stuff private.

Java provides all the API we need for that, we just don’t have any knobs in ColdFusion to switch them on for our Sandboxes

Sane default settings for Sandboxes

If you create a new Sandbox from scratch it has access to many things it shouldn’t. A secure by default configuration would for instance disable all datasources and leave it up to the administrator to enable them on an as needed basis. Same goes for tags like cfexecute and cfobject.

On the other hand the default Sandboxes do not have access to to for instance the /WEB-INF/cftags/ folder. Without that access cfinterface may not work. What is the harm in giving Sandboxes Read and Execute access to that folder by default? Isn’t the code in those folders written by and trusted by Adobe?

There are many more issues that would help ColdFusion becomming a better hosted platform, and I will address a few more in the future, but these are the 4 most important issues in the area of shared hosting security that Adobe needs to address. All of these have been submitted to Adobe, but I am sure a few more votes and ideas won’t hurt.

So far in our attempts to get access to the templates and data of other hosted customers we have primarily focused on accessing the templates of other users in order to get access to their data through them. A more direct approach is to try to access the database directly.

Registered datasources

To access a registered datasource all you need is its name. More often then not, names are easy to guess. Depending on how the datasource is registered in the CF Administrator you may need a username and password as well. If the username and password to the datasource are registered in the ColdFusion Administrator ColdFusion will write them to neo-datasource.xml. They are encrypted there, but with a reversible algorithm (ColdFusion needs to be able to decrypt them in order to authenticate). The way to decrypt these passwords is well known. So if you have read access to neo-datasource.xml through an incorrect Sandbox configuration you have all usernames and passwords registered there.
If the username and password of the datasource are not registered in the ColdFusion Administrator chances are they are stored in the application scope somewhere and we have already seen that the application scope is insecure.

The first line of defense against this is to configure Sandbox Security to only allow access to specific datasources to each Sandbox. This will effectively lock down access from ColdFusion to the datasource, even if you know the full connection string.

Database to database connections

But as good as the protection for datasources is in ColdFusion, it only protects against connections from ColdFusion’s cfquery and cfstoredproc. Just as the trick to work around a disabled cfexecute is to create Java / COM / .NET objects, the trick to work around a disabled ColdFusion datasource connection is to start the connection from somewhere else. And the way to do that is to connect from one database to another. The protocol to do so, SQL/MED, is not widely implemented in databases, but most databases offer proprietary ways to do so. For instance, in MS SQL Server you would use:

FROM OpenDataSource(
  ,Data;User ID=yourusername;Password=yourpassword‘

In PostgreSQL that would be:

FROM dblink(
  , 'SELECT ID, value FROM tables'
  ) AS t1(
  , value TEXT

The one thing that makes this more difficult is that you usually need some sort of superuser privilege on the database server to be allowed to do this.

MS Access

MS Access is a file based database that is pretty popular in shared hosting. While people frequently question performance, scalability and security, it is still an attractive offering because it allows users to download the database, edit it offline and then upload an entirely new database with new data.

MS Access offers a very simple feature to access tables in other MS Access databases without the superuser privileges you would need on a more full-featured database server. You just specify the path to the data file you want to access directly in the query:

FROM table IN 'h:\sites\database.mdb'

What better way to start the new year than with a blog upgrade? Probably the most noticeable feature for you is the new layout. With the switch to a flowed 2-column layout I want to profit from the trend towards wide-screen monitors and use some more room for my code examples. Further I have added a plugin to allow you to subscribe to a thread when you comment so you can get all the responses by email as well. And the last visible change is the addition of gravatars.

Behind the scenes I have upgraded to WordPress 2.7. While I kept up to date on all the security issues by backpatching all the fixes manually (yes, I know PHP too!), the code drift was becomming an issue. And of course I get a lot of new widgets in the administrator. And I have integrated Google Analytics so I can see what sort of content you all like.

On my ToDo list remains the issue of a siutable code highlight plugin with support for CFML so the comming days you may see some expeiments in that area (and occasionally some broken layout).