[SCADASEC] Shedding light onf the Layer 2 OSI protocol

[Jake Brodsky]

And we're using multiple switches and spanning tree to make the best use 
of diverse paths across our plants.  An attack on spanning tree would 
make a mess for us.

As far as I know, there is no way to secure spanning tree protocol.  So 
we're relying on physical security and well defined ports on our 
switches to keep everything going.  Yes, it's primitive; but we need 
some way to handle redundant routes between buildings.

For example, the flow information from the intake of a wastewater plant 
is often used in a feed-forward loop to control the mixed-liquor 
recirculation (MLR) pumps and the aeration blowers.  These three things 
are often geographically separated by many hundreds or even thousands of 
feet.  To ensure connections work we use multiple fiber runs through as 
many different duct banks as we can find.  We then assign one link as 
primary and with the others as alternate paths.

Just thought you'd like to know...

Jake Brodsky

David Barroso wrote:
> Just to add more information, with a simple Spanning Tree attack in a  
> non-secured spanning tree implementation (a normal scenario nowadays),  
> an attacker can smash down the entire network in less than a minute:  
> you will start seeing looped packets until the network is totally  
> unusable. It is not tightly related to SCADA but more and more SCADA  
> gear run over Layer 2 protocols like Spanning Tree and similar.