Fix Your Management Interface

Lets state some facts:

  1. Most of your appliances (Firewalls, ID(P)Ses, Proxies, Email Gateways, Storage Devices, etc) have web interfaces for management
  2. Most vendors recommend that these web interfaces should not be accessible to the public (except those vendors that provide their interfaces over the Internet in some form of *aaS)
  3. All modern browsers provide a function to store your passwords

Now lets make some assumptions:

  1. Many admins are lazy (or just not aware of the risks of these types of interfaces and auto password fields)
  2. Most developers developing these backend web management interfaces are NOT accounting for external threat agents (i.e. – the only people who can access this interface are internal resources)
  3. Many developers are not mitigating against common web attack vectors due to the above


I believe that most appliances are vulnerable to common Cross Site Request Forgery (CSRF – Yeah, It Still Works) attacks. I don’t mean that they’re partially vulnerable by implementing basic (and known to be ineffective) referrer checking, I mean they’re probably not even doing the simple stuff like ensuring that parameters received are from POST requests as opposed to GET requests. I believe this so much that I even offered pints* out to those people finding interfaces without these weaknesses.

We’ve done test after test of appliance interfaces and it’s not even a surprise any more when you find non-idempotent GET methods that simply require an appropriate “Authorization” header to perform functions such as adding a new admin user, resetting the device to factory defaults, or simply shutting down the system. More often than not you don’t even need to lure an administrator into clicking anything, you can just include these GET statements in a bunch of webpages or emails (or RSS feeds) under the clever disguise of an <img> tag.

So come on appliance vendors, pick up your game. Stop trying to imagine that there is a ‘gator-filled-moat between the administrators accessing your products and the nasty web. The browser is the OS, and the people managing your appliances have Twitter and Facebook and God-knows-what open on different tabs. Look, we’ve made it easy for you – just have a read of the OWASP Cross Site Request Forgery Cheat Sheet. Even a little double-serving of Cookies can help (nom nom). Better yet, if you’re building a web management interface for your appliance utilise pre-built security controls, such as OWASP’s Enterprise Security API (ESAPI), this library even comes with FREE anti-CSRF methods? Amazing!

*Nb: You have to come to Perth to collect :)

(This interface goes from Shotgun to Hoover! – Which do you want?)

One thought on “Fix Your Management Interface”

  1. Old post I just came across but I can vouch for this. Shame so many “architects” are horrible at designing secure management networks.

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