Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

66 CHAPTER 4 Wireless Networking
using a unicast session key, and then sent from the AP to the client in a much
more secure manner.
Mutual Authentication
802.1x and EAP provide for a mutual authentication capability. This makes the
clients and the authentication servers mutually authenticating end points, and
assists in the mitigation of attacks from man-in-the-middle (MITM) types of
devices. Any of the following EAP methods provide for mutual authentication:
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TLS requires that the server supply a certificate and establish that it has
possession of the private key.
IKE requires that the server show possession of a preshared key or private
key (this can be considered certificate authentication).
GSS_API (Kerberos) requires that the server can demonstrate knowledge
of the session key.
Per-Packet Authentication
EAP can support per-packet authentication and integrity protection, but it is
not extended to all types of EAP messages. For example, negative acknowledgment
(NACK) and notification messages cannot use per-packet authentication
and integrity. Per-packet authentication and integrity protection works for the
following (packet is encrypted unless otherwise noted):
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TLS and IKE derive session key
TLS cipher suite negotiations (not encrypted)
IKE cipher suite negotiations
Kerberos tickets
Success and failure messages that use a derived session key (through WEP)
COMMON EXPLOITS OF WIRELESS NETWORKS
In general, attacks on wireless networks fall into four basic categories: passive,
active, MITM, and jamming.
Passive Attacks on Wireless Networks
A passive attack occurs when someone listens to or eavesdrops on network traffic.
Passive attacks on wireless networks are extremely common, almost to the point
of being ubiquitous. Detecting and reporting on wireless networks has become
a popular hobby for many wireless war-driving enthusiasts.
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Detecting wireless networks Utilizing new tools created for wireless
networks and the existing identification and attack techniques and utilities
originally designed for wired networks, attackers have many avenues
into a wireless network. The first step in attacking a wireless network
involves finding a network to attack. The most popular software
developed to identify wireless networks is the Windows-based NetStumbler