Protecting the WiFi Network

Wireless IDS

WiFi data channel encryption

Protected Management Frames support

 

Wireless IDS

The FortiGate Wireless Intrusion Detection System (WIDS) monitors wireless traffic for a wide range of security threats by detecting and reporting on possible intrusion attempts. When an attack is detected the FortiGate unit records a log message.

 

You can create a WIDS profile to enable these types of intrusion detection:

• Asleap Attack—ASLEAP is a tool used to perform attacks against LEAP authentication.
• Association Frame Flooding—A Denial of Service attack using a large number of association requests. The default detection threshold is 30 requests in 10 seconds.
• Authentication Frame Flooding—A Denial of Service attack using a large number of association requests. The default detection threshold is 30 requests in 10 seconds.
• Broadcasting De-authentication—This is a type of Denial of Service attack. A flood of spoofed de-authentication frames forces wireless clients to de-athenticate, then re-authenticate with their AP.
• EAPOL Packet Flooding—Extensible Authentication Protocol over LAN (EAPOL) packets are used in WPA and WPA2 authentication. Flooding the AP with these packets can be a denial of service attack. Several types of EAPOL packets are detected: EAPOL-FAIL, EAPOL-LOGOFF, EAPOL-START, EAPOL-SUCC.
• Invalid MAC OUI—Some attackers use randomly-generated MAC addresses. The first three bytes of the MAC address are the Organizationally Unique Identifier (OUI), administered by IEEE. Invalid OUIs are logged.
• Long Duration Attack—To share radio bandwidth, WiFi devices reserve channels for brief periods of time. Excessively long reservation periods can be used as a denial of service attack. You can set a threshold between 1000 and 32 767 microseconds. The default is 8200.
• Null SSID Probe Response—When a wireless client sends out a probe request, the attacker sends a response with a null SSID. This causes many wireless cards and devices to stop responding.
• Spoofed De-authentication—Spoofed de-authentication frames are a denial of service attack. They cause all clients to disconnect from the AP.
• Weak WEP IV Detection—A primary means of cracking WEP keys is by capturing 802.11 frames over an extended period of time and searching for patterns of WEP initialization vectors (IVs) that are known to be weak. WIDS detects known weak WEP IVs in on-air traffic.
• Wireless Bridge—WiFi frames with both the fromDS and ToDS fields set indicate a wireless bridge. This will also detect a wireless bridge that you intentionally configured in your network.

You can enable wireless IDS by selecting a WIDS Profile in your FortiAP profile.

 

To create a WIDS Profile

1. Go to WiFi & Switch Controller > WIDS Profiles.

2. Select a profile to edit or select Create New.

3. Select the types of intrusion to protect against.

By default, all types are selected.

4. Select Apply.

You can also configure a WIDS profile in the CLI using the config wireless-controller wids- profile command.

 

Rogue AP detection

The WIDS profile includes settings for detection of unauthorized (rogue) access points in your wireless network. For more information, see Wireless network monitoring on page 894.

 

 

WiFi data channel encryption

Optionally, you can apply DTLS encryption to the data channel between the wireless controller and FortiAP units. This enhances security.

There are data channel encryption settings on both the FortiGate unit and the FortiAP units. At both ends, you can enable Clear Text, DTLS encryption, or both. The settings must agree or the FortiAP unit will not be able to join the WiFi network. By default, both Clear Text and DTLS-encrypted communication are enabled on the FortiAP unit, allowing the FortiGate setting to determine whether data channel encryption is used. If the FortiGate unit also enables both Clear Text and DTLS, Clear Text is used.

Data channel encryption settings are located in the FortiAP profile. By default, only Clear Text is supported.

Data channel encryption is software-based and can affect performance. Verify that the system meets your performance requirements with encryption enabled.

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