Wireless security has improved over the years, but wireless networks are still susceptible to vulnerabilities. Unfortunately, many users just don’t understand how to lock down a wireless network adequately. If you’re planning to take the SY0-501 version of the Security+ exam, you should understand how to install and configure wireless security settings.
For example, can you answer this question?
Q. You want to implement the STRONGEST level of security on a wireless network. Which of the following supports this goal?
A. Implementing WPA with TKIP
B. Disabling SSID broadcast
C. Enabling MAC filtering
D. Implementing WPA2 with CCMP
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation are available at the end of this post.
Wireless Cryptographic Protocols
Because wireless networks broadcast over the air, anyone who has a wireless transceiver can intercept the transmissions. You can secure wireless networks with several different steps, but the most important step is to implement a strong security protocol, such as Wi-Fi Protected Access II (WPA2). The primary security protocols available for wireless networks includes WPA, WPA2, and TKIP.
WPA
Wi-Fi Protected Access (WPA) was an interim replacement for Wired Equivalent Privacy (WEP). WEP has known vulnerabilities and should not be used. WPA provided an immediate solution to the weaknesses of WEP without requiring users to upgrade their hardware. Even when WPA replaced WEP, its developers recognized that WPA wasn’t solid enough to last for an extended period. Instead, WPA improved wireless security by giving users an alternative to WEP with existing hardware while the developers worked on creating the stronger WPA2 protocol.
WPA is susceptible to password-cracking attacks, especially when the AP has a weak passphrase. The attacker uses a wireless protocol analyzer to capture the authentication traffic and then uses an offline brute force attack to discover the passphrase. Attackers often use a disassociation attack to force the user to reauthenticate.
WPA2
Wi-Fi Protected Access II (WPA2) is the permanent replacement for WPA. WPA2 (also known as IEEE 802.11i) uses stronger cryptography than WPA. The Wi-Fi Alliance requires all devices carrying its WI-FI CERTIFIED logo to meet WPA2 standards, including the use of the Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP).
Although WPA2 provides significant security improvements over previous wireless encryption techniques, some enterprises need stronger security. Another step you can take is to enable authentication with Enterprise mode.
TKIP Versus CCMP
Temporal Key Integrity Protocol (TKIP) is an older encryption protocol used with WPA, and CCMP is a newer encryption protocol used with WPA2. IEEE has deprecated WPA and TKIP due to various security issues, but many wireless networks are still using these older protocols. IEEE recommends using WPA2 with CCMP because it provides significantly more security.
A benefit of TKIP is that it didn’t require new hardware. WEP users could upgrade software and/or firmware and implement WPA with TKIP without the need to replace the hardware. Newer hardware supports WPA2, so the usage of WPA and TKIP is waning. However, you might still see some legacy hardware using WPA and TKIP.
Later implementations of WPA support Advanced Encryption Standard (AES) instead of TKIP. It is a very strong and efficient encryption algorithm. Many applications beyond WPA/WPA2 use AES to provide secure encryption and ensure confidentiality. Several people have been successful at cracking WPA with TKIP, so whenever possible, it’s best to upgrade WPA to WPA2, or at least upgrade TKIP to use AES.
WPA2 supports CCMP, which is based on AES and is much stronger than WPA using TKIP. WPA2 also employs much more secure methods of managing the encryption keys than WPA.
Authentication Protocols
Wireless networks support several different authentication protocols. Many are built on the Extensible Authentication Protocol (EAP), an authentication framework that provides general guidance for authentication methods. IEEE 802.1X servers typically use one of these methods to increase the level of security during the authentication process. Additionally, while they are often used in wireless networks, they can also be used anywhere an 802.1X server is implemented.
A key point to remember for each of the methods is if they support or require certificates. Some methods are EAP, EAP- FAST, PEAP, EAP-TTLS, EAP-TLS, and RADIUS federation.
Note that EAP-Flexible Authentication via Secure Tunneling (EAP-FAST) supports digital certificates, but they are optional. Protected EAP (PEAP) and EAP-Tunneled TLS (EAP-TTLS) require a certificate on the server, but not the clients. EAP-TLS requires certificates on both the servers and the clients. As an introduction, certificates help provide strong authentication and encryption services. However, a Certificate Authority (CA) must issue certificates, so an organization must either purchase certificates from a public CA, or implement a private CA within the network.
Q. You want to implement the STRONGEST level of security on a wireless network. Which of the following supports this goal?
A. Implementing WPA with TKIP
B. Disabling SSID broadcast
C. Enabling MAC filtering
D. Implementing WPA2 with CCMP
Answer is D. Wi-Fi Protected Access II (WPA2) with Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) provides the strongest level of security of the given choices.
Temporal Key Integrity Protocol (TKIP) is an older encryption protocol used with WPA and it isn’t as strong as CCMP.
Disabling service set identifier (SSID) broadcast hides the network from casual users, but attackers can still discover it because the SSID is still included in some packets in plaintext.
Attackers can bypass media access control (MAC) address filtering by spoofing authorized MAC addresses.
See Chapter 4 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide for more information on securing network.