Rogue access point

A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator,^[1] or has been created to allow a hacker to conduct a man-in-the-middle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network.

To prevent the installation of rogue access points, organizations can install wireless intrusion prevention systems to monitor the radio spectrum for unauthorized access points.

Presence of large number of wireless access points can be sensed in airspace of typical enterprise facility. These include managed access points in the secure network plus access points in the neighborhood. Wireless intrusion prevention system facilitates the job of auditing these access points on a continuous basis to find out if there are any rogue access points among them.

In order to detect rogue access points, two conditions need to be tested:

1. whether or not the access point is in the managed access point list
2. whether or not it is connected to the secure network

The first of the above two conditions is easy to test - compare wireless MAC address (also called as BSSID) of the access point against the managed access point BSSID list. However, automated testing of the second condition can become challenging in the light of following factors: a) Need to cover different types of access point devices such as bridging, NAT (router), unencrypted wireless links, encrypted wireless links, different types of relations between wired and wireless MAC addresses of access points, and soft access points, b) necessity to determine access point connectivity with acceptable response time in large networks, and c) requirement to avoid both false positives and negatives which are described below.

False positive (crying wolf) occurs when the wireless intrusion prevention system detects an access point not actually connected to the secure network as wired rogue. Frequent false positives result in wastage of administrative bandwidth spent in chasing them. Possibility of false positives also creates hindrance to enabling automated blocking of wired rogues due to the fear of blocking friendly neighborhood access point.

False negative occurs when the wireless intrusion prevention system fails to detect an access point actually connected to the secure network as wired rogue. False negatives result in security holes.

If an unauthorized access point is found connected to the secure network, it is the rogue access point of the first kind (also called as “wired rogue”). On the other hand, if the unauthorized access point is found not connected to the secure network, it is an external access points. Among the external access points, if any is found to be mischievous or potential risk (e.g., whose settings can attract or have already attracted secure network wireless clients), it is tagged as rogue access point of the second kind, which is often called an "evil twin".

Soft Rogue Access Point

A soft Access Point (soft AP) is set up on a Wi-Fi adapter without the need of a physical Wi-Fi router. With Windows 7 virtual Wi-Fi capabilities and Intel My WiFi technology, one can easily set up a Soft AP on his Windows 7/Windows Vista machine. Once up and running, one can share the network access available on a machine to other Wi-Fi users that will connect to the soft AP. If any employee sets up a soft Access Point on his machine inside the corporate premises and share the corporate network through it, then this soft AP behaves as Rogue AP.^[2]

See also

• Man-in-the-middle attack
• Wireless intrusion prevention system
• Wireless LAN
• Wireless security
• Legality of piggybacking

References

External links

• Roguescanner - Open source network based rogue access point detection
• Wireless security at the Open Directory Project