Lesson 7 B Compare Wireless Security Protocols Flashcards
main problem with wireless?
Wireless LANs require careful configuration to make the connection and transmissions over the link secure. The main problem with wireless is that because it is unguided, there is no way to prevent anything within range from listening to the signals. If the wireless traffic is unencrypted, this could allow the interception of data or the unauthorized use of the network.
Wi-Fi Protected Access (WPA)
The first version of Wi-Fi Protected Access (WPA) was designed to fix critical vulnerabilities in the earlier wired equivalent privacy (WEP) standard. Like WEP, version 1 of WPA uses the RC4 symmetric cipher to encrypt traffic but adds a mechanism called the Temporal Key Integrity Protocol (TKIP) to try to mitigate the various attacks against WEP that had been developed.
WPA2
Neither WEP nor the original WPA version are considered secure enough for continued use. Even with TKIP, WPA is vulnerable to various types of replay attack that aim to recover the encryption key. WPA2 uses the Advanced Encryption Standard (AES) cipher deployed within the Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP). AES replaces RC4 and CCMP replaces TKIP. CCMP provides authenticated encryption, which is designed to make replay attacks harder.
WPA3
Weaknesses have also been found in WPA2, however, which has led to its intended replacement by WPA3. The main features of WPA3 are as follows:
- Simultaneous Authentication of Equals (SAE)—WPA2 uses a 4-way handshake to allow a station to associate with an access point, authenticate its credential, and exchange a key to use for data encryption. This 4-way handshake mechanism is vulnerable to manipulations that allow a threat actor to recover the key. WPA3 replaces the 4-way handshake with the more secure SAE mechanism.
- Updated cryptographic protocols—WPA3 replaces AES CCMP with the stronger AES Galois Counter Mode Protocol (GCMP) mode of operation.
- Protected management frames—Management frames are used for association and authentication and disassociation and deauthentication messages between stations and access points as devices join and leave the network. These frames can be spoofed and misused in various ways under WPA and WPA2. WPA3 mandates use of encryption for these frames to protect against key recovery attacks and DoS attacks that force stations to disconnect.
- Wi-Fi Enhanced Open—An open Wi-Fi network is one with no passphrase. Any station can join the network. In WPA2, this also means that all traffic is unencrypted. WPA3 encrypts this traffic. This means that any station can still join the network, but traffic is protected against sniffing.
Wi-Fi authentication comes in three types:
open, personal, and enterprise.
Within the personal authentication category, there are two methods
WPA2 pre-shared key (PSK) authentication and WPA3 simultaneous authentication of equals (SAE).
WPA2 Pre-Shared Key Authentication
In WPA2, pre-shared key (PSK) authentication uses a passphrase to generate the key that is used to encrypt communications. It is also referred to as group authentication because a group of users shares the same passphrase. When the access point is set to WPA2-PSK mode, the administrator configures a passphrase consisting of 8 to 63 characters. This is converted to a type of hash value, referred to as the pairwise master key (PMK). The same secret must be configured on each station that joins the network. The PMK is used as part of WPA2’s 4-way handshake to derive various session keys.
All types of PSK authentication have been shown to be vulnerable to attacks that attempt to recover the passphrase. The passphrase must be at least 14 characters long to try to mitigate risks from cracking.
WPA3 Personal Authentication
While WPA3 still uses passphrase-based group authentication of stations in personal mode, it provides improvements to the general Wi-Fi encryption, thanks to Simultaneous Authentication of Equals (SAE) replacing the Pre-Shared Key (PSK) authentication method used in prior WPA versions. The encryption with WPA3-Personal is more individualized. Hence users on a WPA3-Personal network can’t ever snoop on another’s WPA3-Personal traffic, even when the user has the Wi-Fi password and is successfully connected.
The main problems with personal modes
ENTERPRISE AUTHENTICATION PROTOCOLS
The main problems with personal modes of authentication are that distribution of the passphrase cannot be secured properly and that the access point administrator may choose an unsecure passphrase. Personal authentication also fails to provide accounting because all users share the same credential.
Extensible Authentication Protocol (EAP)
As an alternative to personal authentication, WPA’s 802.1X enterprise authentication method implements the Extensible Authentication Protocol (EAP). EAP allows the use of different mechanisms to authenticate against a network directory. 802.1X defines the use of EAP over Wireless (EAPoW) to allow an access point to forward authentication data without allowing any other type of network access. It is configured by selecting WPA2-Enterprise or WPA3-Enterprise as the security method on the access point.
Enterprise authentication uses the following general workflow:
- When a wireless station (a supplicant) requests an association, the AP enables the channel for EAPoW traffic only.
- It passes the credentials submitted by the supplicant to an Authentication, Authorization, and Accounting (AAA) server on the wired network for validation. The AAA server (not the access point) determines whether to accept the credential.
- When the user has been authenticated, the AAA server transmits a master key (MK) to the wireless PC or laptop. The wireless station and authentication server then derive the same pairwise master key (PMK) from the MK.
- The AAA server transmits the PMK to the access point. The wireless station and access point use the PMK to derive session keys, using either the WPA2 4-way handshake or WPA3 SAE methods.
The enterprise authentication method means that
The enterprise authentication method means that the access point does not need to store any user accounts or credentials. They can be held in a more secure location on the AAA server. Another advantage of EAP is support for more advanced authentication methods than simple usernames and passwords. Strong EAP methods use a digital certificate on the server and/or client machines. These certificates allow the machines to establish a trust relationship and create a secure tunnel to transmit the user credential or to perform smart card authentication without a user password. This means the system is using strong multifactor authentication.
For example, EAP with Transport Layer Security (EAP-TLS) is one of the strongest types of multifactor authentication:
- Both the server and the wireless supplicant are issued with an encryption key pair and digital certificate.
- On the wireless device, the private key is stored securely in a trusted platform module (TPM) or USB key. The user must authenticate with the device using a PIN, password, or bio gesture to allow use of the key. This is the first factor.
- When the device associates with the network and starts an EAP session, the server sends a digital signature handshake and its certificate.
- The supplicant validates the signature and certificate and if trusted, sends its own handshake and certificate. This is the second factor.
- The server checks the supplicant’s handshake and certificate and authenticates it if trusted.
RADIUS
Remote Authentication Dial-in User Service (RADIUS) is one way of implementing the AAA server when configuring enterprise authentication. The wireless access point is configured as a client of the RADIUS server. Rather than storing and validating user credentials directly, it forwards this data between the RADIUS server and the supplicant without being able to read it. The wireless access point must be configured with the host name or IP address of the RADIUS server and a shared secret. The shared secret allows the RADIUS server and access point to trust one another.
TACACS+
Terminal Access Controller Access Control System Plus (TACACS+) is another way of implementing AAA. TACACS+ was developed by Cisco but is also supported on many third-party implementations. Where RADIUS is often used to authenticate connections by wireless and VPN users, TACACS+ is often used in authenticating administrative access to routers, switches, and access points.
