Rouge AP is an unauthorized AP connected to enterprise wired network. It can allow access to the enterprise wired network from its RF spillage outside of the premises. While it is well established in the mainstream that wired-wireless correlation is the only robust technique to detect such rogue APs, there also have been some wireside-only scanning techniques around to detect rogue APs connected to the enterprise wired network. At first sight, wireside-only scanning appears attractive from cost and deployment perspective as it does not require RF scanners. However the reality is that wireside-only scanning fails to detect many common types of rogues on the wired network.
Recently, the PCI Security Standards Council Wireless Special Interest Group published guidelines to clarify wireless security requirements in PCI DSS 1.2. While these guidelines clearly require using wireless analyzer or wireless IDS/IPS, wireside-only scanning is still sometimes touted, albeit incorrectly, as low cost alternative to meet PCI compliance. Not only does wireside-only scanning violate PCI DSS 1.2 in letter as it does not use wireless scanners, but it also violates it in spirit as it fails to detect many common types of rogues on wired network.
To find out more about how wireside-only scanning works and its limitations please view our technical white paper - Drawbacks of Wireside-only Rogue Detection.