3.6.8 SSID Cloaking and MAC Address Filtering Flashcards
3.6.8 SSID Cloaking and MAC Address Filtering
Wireless signals can travel through solid matter, such as ceilings, floors, walls, outside of the home, or office space. Without stringent security measures in place, installing a WLAN can be the equivalent of putting Ethernet ports everywhere, even outside.
To address the threats of keeping wireless intruders out and protecting data, two early security features were used and are still available on most routers and APs: SSID cloaking and MAC address filtering.
SSID Cloaking
APs and some wireless routers allow the SSID beacon frame to be disabled, as shown in the figure. Wireless clients must manually configure the SSID to connect to the network.
MAC Addresses Filtering
An administrator can manually permit or deny clients wireless access based on their physical MAC hardware address.
3.6.9 802.11 Original Authentication Methods
Although these two features would deter most users, the reality is that neither SSID cloaking nor MAC address filtering would deter a crafty intruder. SSIDs are easily discovered even if APs do not broadcast them, and MAC addresses can be spoofed. The best way to secure a wireless network is to use authentication and encryption systems.
Two types of authentication were introduced with the original 802.11 standard:
Open system authentication - Any wireless client will easily be able to connect. Open system authentication should only be used in situations where security is of no concern, such as those providing free internet access like cafes, hotels, and in remote areas. The wireless client is responsible for providing security such as by using a virtual private network (VPN) to connect securely. VPNs provide authentication and encryption services. VPNs are beyond the scope of this topic.
Shared key authentication - This provides mechanisms such as WEP, WPA, WPA2, and WPA3 to authenticate and encrypt data between a wireless client and AP. However, the password must be pre-shared between both parties to connect.
3.6.10 Shared Key Authentication Methods
There are four shared key authentication techniques available, as described in the table. Until the availability of WPA3 devices becomes ubiquitous, wireless networks should use the WPA2 standard.
3.6.11 Authenticating a Home User
Home routers typically have two choices for authentication: WPA and WPA2. WPA2 is the stronger of the two. The figure shows the option to select one of two WPA2 authentication methods:
Personal - Intended for home or small office networks, users authenticate using a pre-shared key (PSK). Wireless clients authenticate with the wireless router using a pre-shared password. No special authentication server is required.
Enterprise - Intended for enterprise networks but requires a Remote Authentication Dial-In User Service (RADIUS) authentication server. Although more complicated to set up, it provides additional security. The device must be authenticated by the RADIUS server and then users must authenticate using 802.1X standard, which uses the Extensible Authentication Protocol (EAP) for authentication.
3.6.12 Encryption Methods
Encryption is used to protect data. If an intruder has captured encrypted data, they would not be able to decipher it in any reasonable amount of time.
The WPA and WPA2 standards use the following encryption protocols:
Temporal Key Integrity Protocol (TKIP) - TKIP is the encryption method used by WPA. It provides support for legacy WLAN equipment by addressing the original flaws associated with the 802.11 WEP encryption method. It makes use of WEP, but encrypts the Layer 2 payload using TKIP, and carries out a Message Integrity Check (MIC) in the encrypted packet to ensure the message has not been altered.
Advanced Encryption Standard (AES) - AES is the encryption method used by WPA2. It is the preferred method because it is a far stronger method of encryption. It uses the Counter Cipher Mode with Block Chaining Message Authentication Code Protocol (CCMP) that allows destination hosts to recognize if the encrypted and non-encrypted bits have been altered.
3.6.13 Authentication in the Enterprise
In networks that have stricter security requirements, an additional authentication or login is required to grant wireless clients such access. The Enterprise security mode choice requires an Authentication, Authorization, and Accounting (AAA) RADIUS server.
RADIUS Server IP address - This is the reachable address of the RADIUS server.
UDP port numbers - Officially assigned UDP ports 1812 for RADIUS Authentication, and 1813 for RADIUS Accounting, but can also operate using UDP ports 1645 and 1646, as shown in the figure.
Shared key - Used to authenticate the AP with the RADIUS server.
In the figure, the administrator is configuring the wireless router with WPA2 Enterprise authentication using AES encryption. The RADIUS server IPv4 address is configured as well with a strong password to be used between the wireless router and the RADIUS server.
The shared key is not a parameter that must be configured on a wireless client. It is only required on the AP to authenticate with the RADIUS server. User authentication and authorization is handled by the 802.1X standard, which provides a centralized, server-based authentication of end users.
The 802.1X login process uses EAP to communicate with the AP and RADIUS server. EAP is a framework for authenticating network access. It can provide a secure authentication mechanism and negotiate a secure private key which can then be used for a wireless encryption session using TKIP or AES encryption.
3.6.14 WPA3
At the time of this writing, devices that support WPA3 authentication were not readily available. However, WPA2 is no longer considered secure. WPA3, if available, is the recommended 802.11 authentication method. WPA3 includes four applications:
WPA3-Personal
WPA3-Enterprise
Open Networks
Internet of Things (IoT) Onboarding
