Protected Extensible Authentication Protocol
Encyclopedia
The Protected Extensible Authentication Protocol, also known as Protected EAP or simply PEAP, is a protocol that encapsulates the Extensible Authentication Protocol
(EAP) within an encrypted and authenticated Transport Layer Security
(TLS) tunnel
. The purpose was to correct deficiencies in EAP; EAP assumed a protected communication channel, such as that provided by physical security, so facilities for protection of the EAP conversation were not provided.
PEAP was jointly developed by Cisco Systems, Microsoft, and RSA Security. PEAPv0 was the version included with Microsoft
Windows XP
and was nominally defined in draft-kamath-pppext-peapv0-00. PEAPv1 and PEAPv2 were defined in different versions of draft-josefsson-pppext-eap-tls-eap. PEAPv1 was defined in draft-josefsson-pppext-eap-tls-eap-00 through draft-josefsson-pppext-eap-tls-eap-05, and PEAPv2 was defined in versions beginning with draft-josefsson-pppext-eap-tls-eap-06.
The protocol only specifies chaining multiple EAP mechanisms and not any specific method. However, use of the EAP-MSCHAPv2 and EAP-GTC methods are the most commonly supported.
public key certificate
s to authenticate the server. It then creates an encrypted
TLS
tunnel
between the client and the authentication server. In most configurations, the keys for this encryption are transported using the server's public key. The ensuing exchange of authentication information inside the tunnel to authenticate the client is then encrypted and user credentials are safe from eavesdropping.
As of May 2005, there were two PEAP sub-types certified for the updated WPA
and WPA2 standard. They are:
PEAPv0 and PEAPv1 both refer to the outer authentication method and are the mechanisms that create the secure TLS tunnel to protect subsequent authentication transactions. EAP-MSCHAPv2, EAP-GTC, and EAP-SIM refer to the inner authentication methods which provide user or device authentication.
Within Cisco products, PEAPv0 supports inner EAP methods EAP-MSCHAPv2 and EAP-SIM while PEAPv1 supports inner EAP methods EAP-GTC and EAP-SIM. Since Microsoft only supports PEAPv0 and doesn’t support PEAPv1, Microsoft simply calls PEAPv0 PEAP without the v0 or v1 designator. Another difference between Microsoft and Cisco is that Microsoft only supports the EAP-MSCHAPv2 method and not the EAP-SIM method.
However, Microsoft supports another form of PEAPv0 (which Microsoft calls PEAP-EAP-TLS) that Cisco and other third-party server and client software don’t support. PEAP-EAP-TLS requires client installation of a client-side
digital certificate or a more secure smartcard. PEAP-EAP-TLS is very similar in operation to the original EAP-TLS but provides slightly more protection because portions of the client certificate that are unencrypted in EAP-TLS are encrypted in PEAP-EAP-TLS. Ultimately, PEAPv0/EAP-MSCHAPv2 is by far the most prevalent implementation of PEAP, due to the integration of PEAPv0 into Microsoft Windows
products. Cisco's CSSC client now supports PEAP-EAP-TLS.
PEAP has been so successful in the market place that even Funk Software, the defunct inventor and backer of EAP-TTLS, had no choice but to support PEAP in their server and client software for wireless networks.
's Challenge Handshake Authentication Protocol, meaning it allows authentication to databases that support the MS-CHAPv2 format, including Microsoft NT and Microsoft Active Directory.
Behind EAP-TLS, PEAPv0/EAP-MSCHAPv2 is the second most widely supported EAP standard in the world. There are client and server implementations of it from various vendors, including support in all recent releases from Microsoft
, Apple Computer
and Cisco
. Other implementations exist, such as the xsupplicant
from the Open1x.org project, and wpa supplicant
.
As with other 802.1X and EAP types, dynamic encryption can be used with PEAP.
A CA certificate must be used at each client to authenticate the server to each client before the client submits authentication credentials. If the CA certificate is not validated it is generally trivially easy (in wireless networks) to introduce a fake Access Point which allows gathering MS-CHAPv2 handshakes, which on recent hardware can be cracked in a matter of seconds.
OS support. Since Cisco has typically recommended lightweight EAP protocols such as LEAP
and EAP-FAST protocols instead of PEAP, PEAP has not been as widely adopted as some had hoped.
With no interest from Microsoft to support PEAPv1 and no promotion from Cisco, PEAPv1 authentication is rarely used.
Even in Windows 7, released in late 2009, Microsoft has not added support for any other authentication system other than MSCHAPv2.
, there are very few operating system
s with native support for this EAP protocol. Nokia E66
and later mobile phones ship with a version of Symbian
which includes EAP-GTC support.
Extensible Authentication Protocol
Extensible Authentication Protocol, or EAP, is an authentication framework frequently used in wireless networks and Point-to-Point connections. It is defined in RFC 3748, which made RFC 2284 obsolete, and was updated by RFC 5247....
(EAP) within an encrypted and authenticated Transport Layer Security
Transport Layer Security
Transport Layer Security and its predecessor, Secure Sockets Layer , are cryptographic protocols that provide communication security over the Internet...
(TLS) tunnel
Tunneling protocol
Computer networks use a tunneling protocol when one network protocol encapsulates a different payload protocol...
. The purpose was to correct deficiencies in EAP; EAP assumed a protected communication channel, such as that provided by physical security, so facilities for protection of the EAP conversation were not provided.
PEAP was jointly developed by Cisco Systems, Microsoft, and RSA Security. PEAPv0 was the version included with Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
and was nominally defined in draft-kamath-pppext-peapv0-00. PEAPv1 and PEAPv2 were defined in different versions of draft-josefsson-pppext-eap-tls-eap. PEAPv1 was defined in draft-josefsson-pppext-eap-tls-eap-00 through draft-josefsson-pppext-eap-tls-eap-05, and PEAPv2 was defined in versions beginning with draft-josefsson-pppext-eap-tls-eap-06.
The protocol only specifies chaining multiple EAP mechanisms and not any specific method. However, use of the EAP-MSCHAPv2 and EAP-GTC methods are the most commonly supported.
Overview
PEAP is similar in design to EAP-TTLS, requiring only a server-side PKI certificate to create a secure TLS tunnel to protect user authentication, and uses server-sideServer-side
Server-side refers to operations that are performed by the server in a client–server relationship in computer networking.Typically, a server is a software program, such as a web server, that runs on a remote server, reachable from a user's local computer or workstation...
public key certificate
Public key certificate
In cryptography, a public key certificate is an electronic document which uses a digital signature to bind a public key with an identity — information such as the name of a person or an organization, their address, and so forth...
s to authenticate the server. It then creates an encrypted
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
TLS
Transport Layer Security
Transport Layer Security and its predecessor, Secure Sockets Layer , are cryptographic protocols that provide communication security over the Internet...
tunnel
Tunneling protocol
Computer networks use a tunneling protocol when one network protocol encapsulates a different payload protocol...
between the client and the authentication server. In most configurations, the keys for this encryption are transported using the server's public key. The ensuing exchange of authentication information inside the tunnel to authenticate the client is then encrypted and user credentials are safe from eavesdropping.
As of May 2005, there were two PEAP sub-types certified for the updated WPA
Wi-Fi Protected Access
Wi-Fi Protected Access and Wi-Fi Protected Access II are two security protocols and security certification programs developed by the Wi-Fi Alliance to secure wireless computer networks...
and WPA2 standard. They are:
- PEAPv0/EAP-MSCHAPv2
- PEAPv1/EAP-GTC
PEAPv0 and PEAPv1 both refer to the outer authentication method and are the mechanisms that create the secure TLS tunnel to protect subsequent authentication transactions. EAP-MSCHAPv2, EAP-GTC, and EAP-SIM refer to the inner authentication methods which provide user or device authentication.
Within Cisco products, PEAPv0 supports inner EAP methods EAP-MSCHAPv2 and EAP-SIM while PEAPv1 supports inner EAP methods EAP-GTC and EAP-SIM. Since Microsoft only supports PEAPv0 and doesn’t support PEAPv1, Microsoft simply calls PEAPv0 PEAP without the v0 or v1 designator. Another difference between Microsoft and Cisco is that Microsoft only supports the EAP-MSCHAPv2 method and not the EAP-SIM method.
However, Microsoft supports another form of PEAPv0 (which Microsoft calls PEAP-EAP-TLS) that Cisco and other third-party server and client software don’t support. PEAP-EAP-TLS requires client installation of a client-side
Client-side
Client-side refers to operations that are performed by the client in a client–server relationship in a computer network.Typically, a client is a computer application, such as a web browser, that runs on a user's local computer or workstation and connects to a server as necessary...
digital certificate or a more secure smartcard. PEAP-EAP-TLS is very similar in operation to the original EAP-TLS but provides slightly more protection because portions of the client certificate that are unencrypted in EAP-TLS are encrypted in PEAP-EAP-TLS. Ultimately, PEAPv0/EAP-MSCHAPv2 is by far the most prevalent implementation of PEAP, due to the integration of PEAPv0 into Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
products. Cisco's CSSC client now supports PEAP-EAP-TLS.
PEAP has been so successful in the market place that even Funk Software, the defunct inventor and backer of EAP-TTLS, had no choice but to support PEAP in their server and client software for wireless networks.
PEAPv0 with EAP-MSCHAPv2
PEAPv0/EAP-MSCHAPv2 is the most common form of PEAP in use, and what is usually referred to as PEAP. The inner authentication protocol is MicrosoftMicrosoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's Challenge Handshake Authentication Protocol, meaning it allows authentication to databases that support the MS-CHAPv2 format, including Microsoft NT and Microsoft Active Directory.
Behind EAP-TLS, PEAPv0/EAP-MSCHAPv2 is the second most widely supported EAP standard in the world. There are client and server implementations of it from various vendors, including support in all recent releases from Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
, Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
and Cisco
Cisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
. Other implementations exist, such as the xsupplicant
Xsupplicant
Xsupplicant is a supplicant that allows a workstation to authenticate with a RADIUS server using 802.1x and the Extensible Authentication Protocol...
from the Open1x.org project, and wpa supplicant
Wpa supplicant
wpa_supplicant is a free software implementation of an IEEE 802.11i supplicant for Linux, FreeBSD, NetBSD and Microsoft Windows. In addition to being a full-featured WPA2 supplicant, it also implements WPA and older wireless LAN security protocols...
.
As with other 802.1X and EAP types, dynamic encryption can be used with PEAP.
A CA certificate must be used at each client to authenticate the server to each client before the client submits authentication credentials. If the CA certificate is not validated it is generally trivially easy (in wireless networks) to introduce a fake Access Point which allows gathering MS-CHAPv2 handshakes, which on recent hardware can be cracked in a matter of seconds.
PEAPv1 with EAP-GTC
PEAPv1/EAP-GTC was created by Cisco to provide interoperability with existing token card and directory based authentication systems via a protected channel. Even though Microsoft co-invented the PEAP standard, Microsoft never added support for PEAPv1 in general, which means PEAPv1/EAP-GTC has no native WindowsMicrosoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
OS support. Since Cisco has typically recommended lightweight EAP protocols such as LEAP
Lightweight Extensible Authentication Protocol
The Lightweight Extensible Authentication Protocol is a proprietary wireless LAN authentication method developed by Cisco Systems. Important features of LEAP are dynamic WEP keys and mutual authentication...
and EAP-FAST protocols instead of PEAP, PEAP has not been as widely adopted as some had hoped.
With no interest from Microsoft to support PEAPv1 and no promotion from Cisco, PEAPv1 authentication is rarely used.
Even in Windows 7, released in late 2009, Microsoft has not added support for any other authentication system other than MSCHAPv2.
, there are very few operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s with native support for this EAP protocol. Nokia E66
Nokia E66
The Nokia E66 is a slider smartphone in the Nokia Eseries range, a S60 platform third edition device with slide action targeting business users. It is a successor to the Nokia E65 with which it shares many features....
and later mobile phones ship with a version of Symbian
Symbian
Symbian is a mobile operating system and computing platform designed for smartphones and currently maintained by Accenture. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user...
which includes EAP-GTC support.
External links
- draft-kamath-pppext-peapv0 - Microsoft's PEAP version 0
- draft-josefsson-pppext-eap-tls-eap - The EAP-TLS protocol specifications
- Configure RADIUS for secure 802.1x wireless LAN
- How to self-sign a RADIUS server for secure PEAP or EAP-TTLS authentication