WLAN Security

WPA1 and WPA2 security protocols

WPA1 and WPA2 are standards-based security solutions from the Wi-Fi Alliance that

  • provide data protection and access control for wireless LAN systems

  • offer different encryption methods, with WPA1 using TKIP and WPA2 using AES-CCMP, and

  • support multiple authentication options including 802.1X, PSK, and Cisco Centralized Key Management.

WPA1 and WPA2 implementation details

WPA1 is compatible with the IEEE 802.11i standard but was implemented prior to the standard's ratification; WPA2 is the Wi-Fi Alliance's implementation of the ratified IEEE 802.11i standard.

By default, WPA1 uses Temporal Key Integrity Protocol (TKIP) and Message Integrity Check (MIC) for data protection while WPA2 uses the stronger Advanced Encryption Standard encryption algorithm using Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (AES-CCMP). By default, both WPA1 and WPA2 use the 802.1X for authenticated key management. However, the following options are also available:

  • PSK—When you choose PSK (also known as WPA preshared key or WPA passphrase), you need to configure a preshared key (or a passphrase). This key is used as the Pairwise Master Key (PMK) between clients and authentication server.

  • Cisco Centralized Key Management uses a fast rekeying technique that enables clients to roam from one access point to another without going through the controller , typically in under 150 milliseconds (ms). Cisco Centralized Key Management reduces the time required by the client to mutually authenticate with the new access point and derive a new session key during reassociation. Cisco Centralized Key Management fast secure roaming ensures that there is no perceptible delay in time-sensitive applications, such as wireless Voice over IP (VoIP), Enterprise Resource Planning (ERP), or Citrix-based solutions. Cisco Centralized Key Management is a CCXv4-compliant feature. If Cisco Centralized Key Management is selected, only Cisco Centralized Key Management clients are supported.

    When Cisco Centralized Key Management is enabled, the behavior of access points differs from the controller 's for fast roaming in the following ways:

    • If an association request sent by a client has Cisco Centralized Key Management enabled in a Robust Secure Network Information Element (RSN IE) but Cisco Centralized Key Management IE is not encoded and only PMKID is encoded in RSN IE, then the controller does not do a full authentication. Instead, the controller validates the PMKID and does a four-way handshake.

    • If an association request sent by a client has Cisco Centralized Key Management enabled in RSN IE and Cisco Centralized Key Management IE is encoded and only PMKID is present in the RSN IE, then the AP does a full authentication. The access point does not use PMKID sent with the association request when Cisco Centralized Key Management is enabled in RSN IE.

  • 802.1X+Cisco Centralized Key Management—During normal operation, 802.1X-enabled clients mutually authenticate with a new access point by performing a complete 802.1X authentication, including communication with the main RADIUS server. However, when you configure your WLAN for 802.1X and Cisco Centralized Key Management fast secure roaming, Cisco Centralized Key Management-enabled clients securely roam from one access point to another without the need to reauthenticate to the RADIUS server. 802.1X+Cisco Centralized Key Management is considered as an optional Cisco Centralized Key Management because both Cisco Centralized Key Management and non-Cisco Centralized Key Management clients are supported when this option is selected.

On a single WLAN, you can allow WPA1, WPA2, and 802.1X/PSK/Cisco Centralized Key Management/802.1X+Cisco Centralized Key Management clients to join. All of the access points on such a WLAN advertise WPA1, WPA2, and 802.1X/PSK/Cisco Centralized Key Management/ 802.1X+Cisco Centralized Key Management information elements in their beacons and probe responses. When you enable WPA1 and/or WPA2, you can also enable one or two ciphers, or cryptographic algorithms, designed to protect data traffic. Specifically, you can enable AES and/or TKIP data encryption for WPA1 and/or WPA2. TKIP is the default value for WPA1, and AES is the default value for WPA2.

AAA override

AAA override is a WLAN option that enables you to configure the WLAN for identity networking by applying VLAN tagging, Quality of Service (QoS), and Access Control Lists (ACLs) to individual clients based on the returned RADIUS attributes from the AAA server.

Prerequisites for Layer 2 Security

WLANs with the same SSID must have unique Layer 2 security policies so that clients can make a WLAN selection based on the information advertised in beacon and probe responses.

The available Layer 2 security policies are as follows:

  • None (open WLAN)

  • WPA+WPA2


    Note

    • Although WPA and WPA2 cannot be used by multiple WLANs with the same SSID, you can configure two WLANs with the same SSID with WPA/TKIP with PSK and Wi-Fi Protected Access (WPA)/Temporal Key Integrity Protocol (TKIP) with 802.1X, or with WPA/TKIP with 802.1X or WPA/AES with 802.1X.

    • A WLAN configured with TKIP support will not be enabled on an RM3000AC module.

  • Static WEP (not supported on Wave 2 APs)

How to Configure WLAN Security

Configure static WEP Layer 2 security parameters (GUI)

Configure static WEP layer 2 security parameters to secure wireless network communication using WEP encryption keys.

Use this procedure when you need to configure WEP layer 2 security for a WLAN. Static WEP provides basic encryption for wireless communications using either 40-bit or 104-bit encryption keys.

Procedure

Step 1

Choose Configuration > Tags & Profiles > WLANs.

Step 2

On the WLANs page, click the name of the WLAN.

Step 3

In the Edit WLAN window, click the Security tab.

Step 4

From the Layer 2 Security Mode drop-down list, select the Static WEP option.

Step 5

(Optional) Check the Shared Key Authentication check box to set the authentication type as shared. By leaving the check box unchecked, the authentication type is set to open.

Step 6

Set the Key Size as either 40 bits or 104 bits.

  • 40 bits: The keys with 40-bit encryption must contain 5 ASCII text characters or 10 hexadecimal characters.

  • 104 bits: The keys with 104-bit encryption must contain 13 ASCII text characters or 26 hexadecimal characters.

Step 7

Set the appropriate Key Index; you can choose between 1 to 4.

Step 8

Set the Key Format as either ASCII or Hex.

Step 9

Enter a valid Encryption Key.

  • 40 bits: The keys with 40-bit encryption must contain 5 ASCII text characters or 10 hexadecimal characters.

  • 104 bits: The keys with 104-bit encryption must contain 13 ASCII text characters or 26 hexadecimal characters.

Step 10

Click Update & Apply to Device.

The WLAN is configured with static WEP layer 2 security parameters. The settings are applied to the device and WEP encryption is enabled for the wireless network.

Configure static WEP layer 2 security parameters (CLI)

Set up static WEP encryption and authentication for WLAN security.
Static WEP provides basic wireless security through shared encryption keys. This configuration is used when legacy devices require WEP compatibility, though WPA/WPA2 is recommended for better security.

Before you begin

You must have administrator privileges.

Procedure

Step 1

Enter global configuration mode.

Example:

Device# configure terminal

Step 2

Enter WLAN configuration submode.

Example:

Device# wlan profile-name wlan-id SSID-Name

Example:

Device# wlan test4 1 test4

profile-name is the profile name of the configured WLAN.

wlan-id is the wireless LAN identifier. The range is 1 to 512.

SSID_Name is the SSID which can contain 32 alphanumeric characters.

Note

 

If you have already configured this command, enter wlan profile-name command.

Step 3

Disable fast transition.

Example:

Device(config-wlan)# disable ft

Step 4

Disable fast transition over the data source on the WLAN.

Example:

Device(config-wlan)# no security ft over-the-ds

Step 5

Disable 802.11r Fast Transition on the WLAN.

Example:

Device(config-wlan)# no security ft

Step 6

Disable the WPA/WPA2 support for a WLAN.

Example:

Device(config-wlan)# no security wpa wpa1 ciphers tkip

Step 7

Configure Static WEP Key authentication with authentication type.

Example:

Device(config-wlan)# security static-wep-key authentication open

The keywords are as follows:

  • static-wep-key : Configures Static WEP Key authentication.

  • authentication : Specifies the authentication type you can set. The values are open and shared.

Step 8

Configure Static WEP Key encryption parameters.

Example:

Device(config-wlan)# security static-wep-key encryption 104 ascii 0 encryption-key key-index

Example:

Device(config-wlan)# security static-wep-key encryption 104 ascii 0 1234567890123 1

The keywords are as follows:

  • static-wep-key : Configures Static WEP Key authentication.

  • encryption : Specifies the encryption type that you can set. The valid values are 104 and 40. 40-bit keys must contain 5 ASCII text characters or 10 hexadecimal characters. 104-bit keys must contain 13 ASCII text characters or 26 hexadecimal characters.

  • ascii : Specifies the key format as ASCII.

  • hex : Specifies the key format as HEX.

Step 9

Exit configuration mode and return to privileged EXEC mode.

Example:

Device(config-wlan)# end
Static WEP layer 2 security is now configured on the WLAN with the specified authentication and encryption parameters.

Configure WPA + WPA2 Layer 2 security parameters (GUI)

This task configures WPA + WPA2 layer 2 security parameters to secure wireless network communications using the graphical user interface.

Use this procedure when you need to set up wireless network security using both WPA and WPA2 protocols through the GUI interface. This configuration provides enhanced security for your wireless network by supporting both protocols simultaneously.

Procedure

Step 1

Click Configuration > Tags and Profiles > WLANs.

Step 2

Click Add to add a new WLAN Profile or click the one you want to edit.

Step 3

In the Edit WLAN window, click Security > Layer2.

Step 4

From Layer 2 Security Mode drop-down menu, select WPA + WPA2.

Step 5

Configure the security parameters and then click Save and Apply to Device.

The WPA + WPA2 layer 2 security parameters are configured and applied to the device. The WLAN profile now uses both WPA and WPA2 security protocols to protect wireless network communications.

Configure WPA + WPA2 layer 2 security parameters (CLI)

This task configures WPA and WPA2 layer 2 security settings to secure wireless networks using command-line interface commands.


Note

The default values for security policy WPA2 are:

  • Encryption is AES.

  • Authentication Key Management (AKM) is dot1x.

Before you begin

You must have administrator privileges.

Follow these steps to configure WPA + WPA2 layer 2 security parameters using commands:

Procedure

Step 1

Enter global configuration mode.

Example:

Device# configure terminal

Step 2

Enter the WLAN configuration submode.wlan

Example:

Device(config)# wlan profile-name wlan-id SSID_name

Example:

Device(config)# wlan test4 1 test4

  • profile-name is the profile name of the configured WLAN.

  • wlan-id is the wireless LAN identifier. The range is from 1 to 512.

  • SSID_name is the SSID that contains 32 alphanumeric characters.

Note

 

If you have already configured this command, enter wlan profile-name command.

Step 3

Enables WPA or WPA2 support for WLAN.

Example:

Device(config-wlan)# security wpa {akm | wpa1 | wpa2}
Device(config-wlan)# security wpa

Step 4

Enables WPA.

Example:

Device(config-wlan)# security wpa wpa1

Step 5

Specify the WPA1 cipher.

Example:

Device(config-wlan)# security wpa wpa1 ciphers [aes | tkip]
Device(config-wlan)# security wpa wpa1 ciphers aes

Choose one of the following encryption types:

  • aes : Specifies WPA/AES support.

  • tkip : Specifies WPA/TKIP support.

The default values are TKIP for WPA1 and AES for WPA2.

Note

 

You can enable or disable TKIP encryption only using the CLI. Configuring TKIP encryption is not supported in GUI.

When you have VLAN configuration on WGB, you need to configure the encryption cipher mode and keys for a particular VLAN, for example, encryption VLAN 80 mode ciphers TKIP. Then, you need to configure the encryption cipher mode globally on the multicast interface by entering the following command: encryption mode ciphers TKIP.

Step 6

Enable or disable Cisco Centralized Key Management, 802.1x, 802.1x with SHA256 key derivation type, Fast Transition, PSK or PSK with SHA256 key derivation type.security WPA AKM {CCKM| dot1x | dot1x-sha256 | ft | PSK |PSK-sha256}

Example:

Device(config-wlan)# security wpa akm {cckm | dot1x | dot1x-sha256 | ft | psk | psk-sha256}
Device(config-wlan)# security wpa akm psk-sha256

Note

 

  • You cannot enable 802.1x and PSK with SHA256 key derivation type simultaneously.

  • When you configure Cisco Centralized Key Management SSID, you must enable the ccx aironet-iesupport for Cisco Centralized Key Management to work.

  • WPA3 Enterprise dot1x-sha256 is supported only in local mode.

Step 7

Enter this command to specify a preshared key, if you have enabled PSK.

Example:

Device(config-wlan)# security wpa psk set-key {ascii | hex} {0 | 8} password
Device(config-wlan)# security wpa psk set-key ascii 0 test

WPA preshared keys must contain 8 to 63 ASCII text characters or 64 hexadecimal characters.

Step 8

Enable or disable authentication key management suite for fast transition.

Example:

Device(config-wlan)# security wpa akm ft {dot1x | psk | sae}
Device(config-wlan)# security wpa akm ft psk

Note

 

You can now choose between PSK and fast transition PSK as the AKM suite.

Step 9

Enable WPA2.

Example:

Device(config-wlan)# security wpa wpa2

Step 10

Configure WPA2 cipher. security wpa wpa2 ciphers aes

Example:

Device(config-wlan)# security wpa wpa2

Example:

  • aes : Specifies WPA/AES support.

Step 11

show wireless pmk-cache

Displays the remaining time before the PMK cache lifetime timer expires.

If you have enabled WPA2 with 802.1X authenticated key management or WPA1 or WPA2 with Cisco Centralized Key Management authenticated key management, the PMK cache lifetime timer is used to trigger reauthentication with the client when necessary. The timer is based on the timeout value received from the AAA server or the WLAN session timeout setting.

Note

 

  • The command will show VLAN ID with VLAN pooling feature in VLAN-Override field.

  • Sticky key caching (SKC) is not supported.

WPA and WPA2 layer 2 security parameters are configured for the WLAN. The wireless network is secured with the specified authentication and encryption settings.