The Nibble security blog had a very good post on Subverting a Cloud-based Infrastructure with XSS and BEEF. They essentially constructed an XSS attack to issue network infrastructure management commands without user knowledge.

The idea is pretty neat: all network devices and security appliances (wired and wireless) can be managed by a cutting-edge web interface hosted in the cloud, allowing Meraki networks to be completely set up and controlled through the Internet. Many enterprises, universities and numerous other businesses are already using this technology. As usual, new technologies introduce opportunities and risks. In such environments, even a simple Cross-Site Scripting or a Cross-Site Request Forgery vulnerability can affect the overall security of the managed networks.

There are two important takeaways here, so don’t get caught up with a specific vendor’s vulnerabilities or the specific tool used to craft this attack. The management interfaces for all cloud services are browser-accessible, and browsers – and the web services they use – are open to these attacks. XSS and CSRF are major issues, and we have considerable evidence – the Mandiant report being just one source – that browser-based attacks are one of the top two current attack vectors. These are problems that most organizations don’t consider when building web applications, so they are common vulnerabilities.

Which leads directly into the second issue: that all cloud services, by definition, offer broad network access. That means applications and management interfaces are both browser accessible. The beauty of cloud services for IT management is that you can access all cloud management functions from any browser, anywhere. And from that single connection you do just about anything. Very convenient! For attackers too – once they compromise a customer’s management plane for a cloud service, that is equivalent to root access. Only in this case it’s the entire cloud infrastructure, not just one server. Because the attack originates from your browser, it does not matter whether you restricted management access to in-house IP addresses – your system has one of the approved IP addresses.

There are not many quick and easy ways to protect against this type of attack, but use a dedicated browser for management if you can. Other than that … be careful what you surf for.