This post will be broken into five (including this one) smaller posts. This is taking me far longer than I imagined to finish “Switch Security” (the last section of work before revision) as a section and I have had a few too many close calls in losing this draft post as it gets bigger and bigger.
Security has in the past been focused from the outside in and at the upper layers of the OSI model. Think of the deployment in most situations of a firewall (at the edge). Firewall and security devices often focus on edge routing devices and layer-3 and layer-4 information, stateful packet inspection, etc.
This being said internal communication is often open and unhindered. This is because out of the box “internal” trusted devices forward and just “trust” all. If an attack is launched from inside the network (trusted) then it often goes without notice for a long time. Many security features are available for internal network devices but they must be activated to work.
With the large scale adoption of Access Points (APs) and other Wireless devices many employees want the same devices at work as those they enjoy at home. This brings with it the problem of employees plugging wireless AP devices into the office network (Malicious Rogues) when the IT department has no knowledge and has not given consent for these devices to operate on the enterprise network. This is a serious breach of company security because the APs are plugged into a network point (trusted) behind the firewall (untrusted) intentionally hidden from view (behind credenzas, filing cabinets, etc) and network view (SMTP, etc). Because John Doe office employee isn’t thinking about the L33t Hacker or Security ramifications they make the wireless AP work (without any security measures whatsoever).
To mitigate against Spanning Tree Protocol (STP) manipulation, use root guard and the BPDU guard enhancement commands. These commands enforce the placement of the root bridge in the network and enforce the STP domain borders. BPDU guard is best deployed towards user-facing ports to prevent rogue switch-network extensions by an attacker.
Notes and Notices:
This is a part of my personal BCMSN notes and research to assist myself in learning and understanding the concepts and theory for the BCMSN exam. I learn by making notes reading and writing things down and wish to file them where I can’t lose them. These notes are not to be seen, judged or mistaken for replacements to Cisco recognized and authorized training which I personally support and attend and suggest you undertake if you are going for the BCMSN Certification.