The Unofficial 802.11 Security Web Page

Last update: June 22, 2009

Lots of people are interested in wireless LAN security nowadays. Given that level of interest, there's a need for accurate information on how the current standards work, what's wrong with them, and the current thinking on how to fix the problems. This site tries to gather relevant papers and standards in a single place.

Trends and overview

Ethernet Everywhere

Ethernet is on the verge of becoming the preferred technology for LAN (wired and wireless), SAN, MAN and WAN. Increasing in speed by an order of magnitude every 3 years, "Ethernet Everywhere" could be to the next decade what "IP everywhere" was to the 1990s.

IEEE 802.1X "network Port Authentication" was designed to scale with Ethernet, adding no per-packet overhead, and bringing the management technology of dialup networks to the wired and wireless LAN worlds. Here are presentations on the current trends in Ethernet network access, both wired and wireless, and an introduction to IEEE 802.1X and its applications.

Ethernet Everywhere!
Wireless World 2001 and BAWUG Presentations on IEEE 802.1X

Thinking about network access authentication

Here's a presentation on how we do authentication for network access and why this is most often handled at layer 2 (PPP, IEEE 802.1X) rather than at layer 1 (802.11) or at layer 3 (Mobile IP) or higher.

BURP BOF presentation at IETF 50

IEEE 802 Standards

IEEE 802.1 standards
IEEE 802.11 standards
IEEE 802.16 standards

Other 802.11 Web sites

Raul Siles Wifi Website

WEP security issues

You've read all about the security problems with WEP. Here are the papers and presentations that lay out the problem.

War Driving Tools
A summary presentation on WEP security issues (from 802.11 Tgi)
Berkeley WEP Security Analysis Presentation (PDF)
Bill Arbaugh's paper on cracking WEP (PDF)
Fluhrer, Mantin and Shamir's paper on cracking WEP
Jesse Walker's "Unsafe at any key length" paper
Possible ways of improving WEP (near impossible)

Wi-fi Protected Access (WPA)

The WiFi Alliance (WFA) is now certifying an interim draft of the 802.11 security specification, known as Wi-fi Protected Access (WPA). There are also pre-WPA implementations in the market, some of which have known vulnerabilities. Here are the details of the WPA specification and the known security vulnerabilities:

WPA

Details on WPA can be found here:

WPA Web Site (includes links to the specification)
Microsoft WPA Support
NDIS WLAN Objects

WPA Security Vulnerabilities

Details of WPA security vulnerabilities can be found here:

Issues with Pre-WPA implementations
Michael Attacks and Countermeasures
PSK-mode dictionary attack vulnerability
Weaknesses in the WPA Temporal Key Hash

IEEE 802.11i

The IEEE 802.11i standard was approved in July, 2004. Here are pointers to the specification and its vulnerabilities:

IEEE 802.11i specification (Approved as an IEEE 802.11 Standard)
IEEE 802.11i Overview
NIST Security Workshop

IEEE 802.11i Security Vulnerabilities

Details of IEEE 802.11i security vulnerabilities can be found here:

One Message Attack on the 4-way Handshake
Analysis of the 4-way Handshake (Paper)
Summary of Security Issues

IEEE 802.1X "Network Port Authentication"

IEEE 802.1X is an IEEE standard (approved, June 2001) that enables authentication and key management for IEEE 802 Local Area Networks, including Ethernet, Token Ring, and FDDI. Since the IEEE 802.11 Task Group I security work had only just gotten underway at the time that the IEEE 802.1X standard was approved, 802.1X does not describe how the 802.1X and 802.11 state machines are to be coupled. That task was left to IEEE 802.11 Task Group I.

Since IEEE 802.1X is not a cipher, it is not an alternative to WEP, 3DES, AES, or any other cipher. Since IEEE 802.1X is only focused on authentication and key management, it does not specify how or when security services are to be delivered using the derived keys. However, it can be used to derive authentication and encryption keys for use with any cipher, and can also be used to periodically refresh keys and re-authenticate so as to make sure that the keying material is "fresh".

IEEE 802.1X is not a single authentication method; rather it utilizes Extensible Authentication Protocol (EAP) as its authentication framework. This means that 802.1X-enabled switches and access points can support a wide variety of authentication methods, including certificate-based authentication, smartcards, token cards, one-time passwords, etc. However, the 802.1X specification itself does not specify or mandate any authentication methods. Since switches and access points act as a "pass through" for EAP, new authentication methods can be added without the need to upgrade the switch or access point, by adding software on the host and backend authentication server.

Since IEEE 802.1X doesn't involve encapsulation (unlike PPPOE or VPN) it adds no per-packet overhead and can be implemented on existing switches and access points with no performance impact. This means that IEEE 802.1X can scale from speeds of 11 Mbps (802.11) to 10+ Gbps, and can be enabled on existing switches with a firmware upgrade, without the need to buy new hardware. On hosts, since IEEE 802.1X can be implemented in the NIC driver, support can be enabled by obtaining updating drivers from the NIC vendor; there is no need to install a new operating system.

IEEE 802.1X integrates well with open standards for authentication, authorization and accounting (including RADIUS and LDAP) and so it fits in well with existing infrastructure for managing dialup networks and VPNs. RADIUS servers (including Windows 2000 IAS) that support EAP can be used to manage IEEE 802.1X-based network access.

These specifications describe how IEEE 802.1X works, and how it can be managed via RADIUS and SNMP. Through RADIUS, IEEE 802.1X permits management of authorization on a per-user basis. Per-user services include filtering (layer 2 or layer 3), tunneling, dynamic VLANs, rate limits, etc.

IEEE 802.1X-2004 (Approved as an IEEE 802.1 Standard)
IEEE 802.1X-2004 MIB
IEEE 802.1X-2001 MIB (IEEE 802 Standard)
IEEE 802.1X-2001 (IEEE 802 Standard)
Some thoughts on diagnosing problems via the 802.1X MIB
IEEE 802/802.1X Architecture Issues (Draft, work in progress)

802.1X Implementations

Open 802.1X
WIRE1X

IETF/IEEE 802 Liaison

IEEE 802 and IETF communicate regularly relating to IETF dependencies of IEEE 802 working groups. Here is some information relating to the liaison relationship:

Miscellaneous Topics

VPN Standards and Security Analyses

You've probably heard "experts" say that "VPN is the answer to WEP security problems." Well, it isn't that simple -- because the next question is "whose VPN?" Almost all IPsec tunnel mode products shipping today are proprietary, interoperability is poor and many of the proprietary extensions have security flaws. Here are the references to the security analyses of VPN protocols as well as to the IETF standards for VPN. Ask your vendors when they plan to implement the IETF standards!

Security analysis of PPTPv2
Security analysis of PPTP
Microsoft point of view on PPTP
Security analysis of XAUTH (shipping in most IPsec tunnel mode implementations)
Man-in-the-middle attacks against IPsec VPNs (also SSH, HTTPS, etc.)
Configuration of IPsec tunnel mode with DHCPv4 (Proposed Standard, RFC 3456)
Securing L2TP with IPsec (Proposed Standard, RFC 3193)
Legacy authentication within IPsec tunnel mode (PIC) (Internet Draft, work in progress)
IPsec-NAT compatibility requirements (Informational, RFC 3715)

Credential provisioning

Recently, there has been a lot of interest in the application of certificates to WLAN authentication. Here are some presentations and papers on the subject:

IETF 55 Enrollment Workshop
Certificate-based roaming (Internet Draft, work in progress)
Certificate hierarchy for the WLAN industry (presentation to IEEE 802.11 Tgi)
WLAN certificate extensions (Proposed Standard, RFC 4334)
Why Certificate OIDs are needed
PEAPOD proposal for EAP-based enrollment