EAP-TTLS-PAP

What is Expansion of EAP-TTLS-PAP?

Extensible Authentication Protocol - Tunneled Transport Layer Security - Password Authentication Protocol.

What is EAP-TTLS-PAP?

EAP-TTLS-PAP is an authentication method that establishes a secure TLS tunnel using EAP-TTLS, inside which the PAP protocol is used for transmitting username and password credentials.

Why is EAP-TTLS-PAP useful?

  • Secures otherwise insecure PAP password authentication by encapsulating it inside a TLS tunnel.

  • Protects credentials from eavesdropping and replay attacks.

  • Provides compatibility with legacy systems using PAP without exposing plaintext credentials on the network.

  • Does not require client certificates, easing deployment.

How it works?

  1. Client and server perform a TLS handshake via EAP-TTLS to create a secure tunnel.

  2. Inside this encrypted tunnel, PAP credentials (username and password) are sent from client to server.

  3. The server validates the credentials and authenticates the user.

  4. Upon success, session keys are derived for securing the connection.

Where is EAP-TTLS-PAP used?

  • Enterprise wireless networks needing to support legacy PAP authentication securely.

  • Networks transitioning from less secure authentication methods.

  • Environments where client certificates are not feasible but TLS security is desired.

Which OSI layer does this protocol belong to?

Application Layer (Layer 7).

Is EAP-TTLS-PAP windows specific?

No. EAP-TTLS-PAP is supported across multiple platforms, including Windows, Linux, and macOS.

Is EAP-TTLS-PAP Linux Specific?

No. Supported by Linux supplicants (e.g., wpa_supplicant) and RADIUS servers like FreeRADIUS.

Which Transport Protocol is used by EAP-TTLS-PAP?

  • EAPOL (EAP over LAN) between supplicant and authenticator.

  • RADIUS protocol over UDP between authenticator and authentication server.

Which Port is used by EAP-TTLS-PAP?

UDP port 1812 (RADIUS authentication).

Is EAP-TTLS-PAP using Client server model?

Yes. Involves client (supplicant), authenticator (access point), and authentication server.

Whether EAP-TTLS-PAP protocol uses certificates?

Server certificates are mandatory to establish the TLS tunnel. Client certificates are not used.

How many frame exchanges are seen during connection for EAP-TTLS-PAP protocol?

Approximately 20-30 EAPOL frame exchanges, including TLS handshake and PAP exchange inside the tunnel.

Whether EAP-TTLS-PAP Protocol uses client certificates?

No, client certificates are generally not used.

Whether EAP-TTLS-PAP Protocol uses Server Certificates?

Yes, server certificates are used to authenticate the server and set up TLS.

Is EAP-TTLS-PAP Protocol depends on TCP?

Not directly. EAPOL is Layer 2, TLS handshake is over EAP messages, and RADIUS uses UDP.

Is EAP-TTLS-PAP Protocol depends on UDP?

Yes, RADIUS uses UDP between authenticator and authentication server.

What are the roles involved when testing EAP-TTLS-PAP Protocol?

  • Supplicant with PAP credentials.

  • Access Point or authenticator.

  • RADIUS server supporting EAP-TTLS with PAP.

  • Certificate authority for server certs.

  • Network analysis tools for debugging.

Does EAP-TTLS-PAP Protocol work with free radius server on Linux?

Yes, FreeRADIUS supports EAP-TTLS-PAP.

Does EAP-TTLS-PAP Protocol work with Internal radius server of hostapd?

Limited support; external RADIUS servers are preferred.

What is the RFC version use for EAP-TTLS-PAP Protocol?

RFC 5281 (EAP-TTLS).

During Connection Procedure which EPoL Packets are encrypted?

Only packets inside the TLS tunnel (including PAP credentials) are encrypted.

Can you Explain different stages of Connection Procedure for EAP-TTLS-PAP Protocol?

  1. Client initiates EAP-TTLS and verifies server certificate.

  2. TLS tunnel is established.

  3. Client sends PAP username and password inside the tunnel.

  4. Server verifies credentials.

  5. Upon success, PMK is generated.

  6. 4-way handshake completes to secure wireless session.

What is the final output of Connection Procedure?

Successful user authentication and derivation of the Pairwise Master Key (PMK).

What is the format of the key generate after the connection procedure?

A 256-bit Pairwise Master Key (PMK).

Where the use of PMK generated by the Connection Procedure?

The PMK is used during the 4-way handshake to derive encryption keys for securing the wireless data transmission.

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • rfc details

  • Run Free RADIUS

FreeRADIUS: Download latest freeradius source code

Note

  • Make sure internet is available in laptop to download freeradius package

test:~$ wget https://github.com/FreeRADIUS/freeradius-server/archive/v3.0.x.tar.gz

FreeRADIUS: Extract freeradius

test:~$ tar -zvf v3.0.x.tar.gz

FreeRADIUS: Change directory to Radius server

test:~$ cd freeradius-server-3.0/

FreeRADIUS: Check the current working directory using pwd command

Note

  • Make sure your current working directory is freeradius-server-3.0

test:~$ pwd
/home/test/freeradius-server-3.0

FreeRADIUS: Open debian/rules and add this line –without-rml_sql_iodbc above –without-rlm_eap_ikev2

test:~$ vim debian/rules
--without-rml_sql_iodbc \
--without-rlm_eap_ikev2 \

FreeRADIUS: Configure for Compilation

test:~$ ./configure

FreeRADIUS: Build the Radius server

test:~$ make

FreeRADIUS: Go to raddb folder (all radius server/client files and certificates and keys will be generated here)

test:~$ cd /usr/local/etc/raddb

FreeRADIUS: Open clients.conf file and verify localhost client is present else add your own client like below

test:~$ sudo vi clients.conf

client 192.168.56.10{
ipaddr = 192.168.56.10
secret = testing123
}  

FreeRADIUS: Open users file and uncomment below two lines or add

test:~$ sudo vi users

bob 	Cleartext-Password := "testing123"
 	Reply-Message := "Hello, %{User-Name}"

FreeRADIUS: Set default_eap_type=tls in eap file located in /usr/local/etc/raddb/mods-enabled

test:~$ sudo vi /usr/local/etc/raddb/mods-enabled/eap

default_eap_type=ttls

FreeRADIUS: Start radius server

test:~$ sudo radiusd -X
  • Run AP mode operation with hostapd

AP : Download hostapd

Note

  • Make sure internet is available in laptop to download hostapd package

test:~$ wget http://w1.fi/releases/hostapd-2.9.tar.gz

AP: Install required packages

test:~$ sudo apt install libnl-genl-3-dev libnl-3-dev libdbus-glib-1-dev

AP : Extract hostapd

test:~$ tar -xzvf hostapd-2.9.tar.gz

AP : Change directory to hostapd

test:~$ cd hostapd-2.9/hostapd/

AP : Check the current working directory using pwd command

Note

  • Make sure your current working directory is hostapd

test:~$ pwd
/home/test/hostapd-2.9/hostapd

AP : Copy the contents of defconfig file to .config file

Note

  • .config file is required for make to start compilation of hostapd

test:~$ sudo cp defconfig .config

AP : Complile hostapd

Note

  • Compile hostapd by running make command

test:~$ make

AP : Check for the binaries created

Note

  • Make sure hostapd and hostapd_cli are present

test:~$ ls
hostapd
hostapd_cli

AP : Create a hostapd.conf file in /etc/hostapd folder with below content

test:~$ sudo vim /etc/hostapd/hostapd.conf

ctrl_interface=/var/run/hostapd
interface=enp0s8
driver=wired
logger_stdout=1
logger_stdout_level=1
debug=2
ieee8021x=1
eap_server=0
eap_user_file=/etc/hostapd/eap_user
eap_reauth_period=3600
use_pae_group_addr=1
auth_algs=1
auth_server_addr=127.0.0.1
auth_server_port=1812
auth_server_shared_secret=testing123
acct_server_addr=127.0.0.1
acct_server_port=1812
acct_server_shared_secret=testing123
macaddr_acl=0
ca_cert=/usr/local/etc/raddb/certs/ca.pem
server_cert=/usr/local/etc/raddb/certs/server.crt
private_key=/usr/local/etc/raddb/certs/server.p12
private_key_passwd=whatever 

AP : Create a file eap_user in /etc/hostapd/ folder with below content

test:~$ sudo vim /etc/hostapd/eap_user

AP : Run hostapd

test:~$ sudo ./hostapd /etc/hostapd/hostapd.conf
enp0s8: interface state UNINITIALIZED->ENABLED
enp0s8: AP-ENABLED

STA : Download wpa_supplicant

Note

  • Make sure internet is available in laptop to download supplicant package

test:~$ wget https://w1.fi/releases/wpa_supplicant-2.9.tar.gz

STA: Install required packages

test:~$ sudo apt install libnl-genl-3-dev libnl-3-dev libdbus-glib-1-dev

STA : Extract wpa_supplicant

test:~$ tar -xvf wpa_supplicant-2.9.tar.gz

STA : Change directory to wpa_supplicant

test:~$ cd wpa_supplicant-2.9/wpa_supplicant/

STA : Check the current working directory using pwd command

Note

  • Make sure your current working directory is wpa_supplicant

test:~$ pwd
/home/test/wpa_supplicant-2.9/wpa_supplicant

STA : Copy the contents of defconfig file to .config file

Note

  • .config file is required for make to start compilation of supplicant

test:~$ cp defconfig .config

STA : Compile wpa_supplicant

Note

  • Compile supplicant by running make command.

test:~$ make

STA: You might get errors while make regarding openssl headers in that case install the openssl headers and then do make clean and then do make again.

test:~$ sudo apt install libssl-dev
test:~$ make clean
test:~$ make

STA : Check for the binaries created

Note

  • Make sure wpa_supplicant and wpa_cli are present

test:~$ ls
wpa_supplicant
wpa_cli

STA: Copy required certificates from hostapd to wpa_supplicant

STA : Create wpa_supplicant.conf

test:~$ sudo vim wpa_supplicant.conf

ctrl_interface=/run/wpa_supplicant
update_config=1
network={
key_mgmt=WPA-EAP
eap=TTLS
phase2="auth=PAP"
identity="bob"
password="testing123"
}

STA : Run wpa_supplicant

test:~$ sudo ./wpa_supplicant -D wired -i enp0s8 -c wpa_supplicant.conf
enp0s8: CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully

STA: Test

test:sudo ./wpa_cli -i enp0s8
> status
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