I’ve spent the past far-too-many years working in the finance industry, in mega-banks and card processors. These companies are traditionally very worried about information security. It’s not to say they always do it well (everyone makes a mistake), but it leads to a conservative attitude. These types of companies end up creating a massive set of standards and procedures to protect themselves. “Thou MUST do this. Thou MUST do that.
Even after all this time I hear statements like “Oh, we can just run our code in the cloud”. This is the core of the lift and shift school of cloud usage. And these people are perfectly correct; they can just run their stuff in the cloud. But it won’t work so well. I’ve previously written about lift and shift issues, but here I want to focus on the “resiliency” issue.
Unless you’ve been living under a rock, you may have heard of two panic panic panic bugs, known as Meltdown and Spectre. People are panicking about them because they are CPU level issues that may impact almost every modern CPU around. Meltdown is Intel specific, but Spectre affects Intel, AMD, and potentially others (Redhat claims POWER and zSeries is impacted). What is the problem? In short, modern CPUs may execute instructions out of order, especially when the order doesn’t matter.
It’s a fairly common design in enterprise networks; a three tier network architecture, with firewalls between the tiers. Typically these layers are split up with variations of the following names: Presentation Layer (Web) Application Layer (App) Data (or storage) Layer (Data) Typically you may have additional tooling in front of each layer; e.g a load balancer, a web application firewall, data loss protection tools, intrusion detection tools, database activity monitoring…
“Those who cannot remember the past are condemned to repeat it.” – George Santayana Default broken I was reminded, last week, of how old issues repeat. Back in the 90s it was a truism that if you put an “Out Of The Box” RedHat 4 (not RedHat Enterprise; the original freeware version) server on the internet then it would be compromised within hours. And so we learned; our default builds didn’t have telnet, didn’t have every possible service installed, didn’t have vulnerable configurations.
One of the golden rules of IT security is that you need to maintain an accurate inventory of your assets. After all, if you don’t know what you have then how you can secure it? This may cover a list of physical devices (servers, routers, firewalls), virtual machines, software… An “asset” is an extremely flexible term and you need to look at it from various viewpoints to ensure you have good knowledge of your environment.
A while ago I wrote about some of the technology basics that can be used for data persistency. Apparently this is becoming a big issue, so I’m revisiting this from another direction. Why does this matter? In essence, an application is a method of changing data from one state to another; “I charge $100 to my credit card” fires off a number of applications that result in my account being debited, and the merchant being credited.
Part of any good backup strategy is to ensure a copy of your backup is stored in a secondary location, so that if there is a major outage (datacenter failure, office burns down, whatever) there is a copy of your data stored elsewhere. After all, what use is a backup if it gets destroyed at the same time as the original? A large enterprise may do cross-datacenter backups, or stream them to a “bunker”; smaller business may physically transfer media to a storage location (in my first job mumble years ago, the finance director would take the weekly full-backup tapes to her house so we had at most 1 week of data loss).
A typical cloud engagement has a dual responsibility model. There’s stuff that can be considered “below the line” and is the responsibility of the cloud service provider (CSP) and there’s stuff above the line, which is the responsibility of the customer. Amazon have a good example for their IaaS: Where the line lives will depend on the type of engagement; the higher up the abstraction tree (IaaS->PaaS->SaaS) the more the CSP has responsibility.
In a previous blog entry I described some of the controls that are needed if you want to use a container as a VM. Essentially, if you want to use it as a VM then you must treat it as a VM. This means that all your containers should have the same baseline as your VM OS, the same configuration, the same security policies. Fortunately we can take a VM and convert it into a container.
In a lot of this blog I have been pushing for the use of containers as an “application execution environment”. You only put the minimal necessary stuff inside the container, treat them as immutable images, never login to them… the sort of thing that’s perfect for 12 factor application. However there are other ways of using containers. The other main version is to treat a container as a light-weight VM.
A phrase you might hear around cloud computing is lift and shift. In this model you effectively take your existing application and move it, wholesale, into a cloud environment such as Amazon EC2. There’s no re-architecting of the application; there’s no application redesign. This make it very quick and very easy to move into the cloud. It’s not much different to a previous p2v (physical to virtual) activity that companies performed when migration to virtual servers (eg VMware ESX).
In this glorious new world I’ve been writing about, applications are non persistent. They spin up and are destroyed at will. They have no state in them. They can be rebuilt, scaled out, migrated, replaced and your application shouldn’t notice… if written properly! But applications are pointless if they don’t have data to work on. In traditional compute an app is associated with a machine (or set of machines). These machines have filesystems.
The core problem with a public cloud is “untrusted infrastructure”. We could get a VM from Amazon; that’s easy. What now? The hypervisor isn’t trusted (non company staff access it and could use this to bypass OS controls). The storage isn’t trusted (non company staff could access it). The network isn’t trusted (non company…). So could we store Personal Identifying Information in the cloud? Could a bank store your account data in a public cloud?