The chairman of the Standards Working Group for IEEE’s 802.11 — the wireless standard used in Apple’s AirPort system — has released a statement regarding a recent report of a security hole in the technology that could expose corporate computer networks to eavesdropping and unauthorized access.
In the statement, Stuart Kerry addresses many of the concerns and points addressed in a report recently released by a small research group in the Computer Science Division at the University of California, Berkeley.
Kerry and the standards committee feels the report has given “some misconceptions on this topic that are now spreading through the media,” and that IEEE 802.11’s Wired Equivalent Privacy (WEP) standard was developed to have the same level of security as wired Local Area Networks (LANs).
“WEP is not intended to be a complete security solution, but, just as with physical security in the wired LAN case, should be supplemented with additional security mechanisms such as access control, end-to-end encryption, password protections, authentication, virtual private networks, and firewalls, whenever the value of the data being protected justifies such concern,” Kerry wrote.
The standards committee feels an attack on WEP security would be difficult to achieve, but could be done with “enough time and money.” Given that, the committee feels the payoff could be very limited. “It is not clear at all whether the payoff to the attacker after marshalling the resources to mount such an attack would necessarily justify the expense of the attack…”
The committee concluded that if there is a fear of a possible security break-in, users of wireless systems such as AirPort should use protection mechanisms like WEP, which it feels offers one of the best levels of security available today, despite criticism of its vulnerability.
Here is the statement released by Kerry and the Standards Working Group for Wireless Local Area Networks:
Subject: WLAN/ Response of WEP Security
Response from the IEEE 802.11 Chair on WEP Security
Recent reports in the press have described the results of certain research efforts directed towards determining the level of security achievable with the Wired Equivalent Privacy algorithm in the IEEE 802.11 Wireless LAN standard. While much of the reporting has been accurate, there have been some misconceptions on this topic that are now spreading through the media. Befitting the importance of the issue, I am inclined to make a response from the Chair to clarify these issues with the following points:
1. Contrary to certain reports in the press, the development of WEP as an integral part of the IEEE 802.11 standard was accomplished through a completely open process. Like all IEEE 802 standards activities, participation is open to all interested parties, and indeed the IEEE 802.11 committee has had a large and active membership.
2. The acronym WEP stands for Wired Equivalent Privacy, and from the outset the goals for WEP have been clear, namely to provide an equivalent level of privacy as is ordinarily present with a wired LAN. Wired LANs such as IEEE 802.3 (Ethernet) are ordinarily protected by the physical security mechanisms within a facility (such as controlled entrances to a building), and the IEEE wired LAN standards do not incorporate encryption. Wireless LANs are not necessarily protected by physical security, and consequently to provide an equivalent level of privacy it was decided to incorporate WEP encryption into the IEEE 802.11 standard. However, recognizing that the level of privacy afforded by physical security in the wired LAN case is limited, the goals of WEP are similarly limited. WEP is not intended to be a complete security solution, but, just as with physical security in the wired LAN case, should be supplemented with additional security mechanisms such as access control, end-to-end encryption, password protections, authentication, virtual private networks, and firewalls, whenever the value of the data being protected justifies such concern.
3. Given the goals for Wired Equivalent Privacy, WEP has been, and continues to be, a very effective deterrent against the vast majority of attackers that might attempt to compromise the privacy of a wireless LAN, ranging from casual snoopers to sophisticated hackers armed with substantial money and resources.
4. The active attacks on WEP reported recently in the press are not simple to mount. They are attacks, which could conceivably be mounted given enough time and money. The attacks in fact appear to require considerable development resources and computer power. It is not clear at all whether the payoff to the attacker after marshalling the resources to mount such an attack would necessarily justify the expense of the attack, particularly given the presence of cheaper and simpler alternative attacks on the physical security of a facility. Key management systems also reduce the window of these attacks succeeding.
5. In an enterprise or other large installation, the complete set of security mechanisms typically employed in addition to WEP would make even a successful attack on WEP of marginal value to the attacker.
6. In a home environment, the likelihood of such an attack being mounted is probably negligible, given the cost of the attack versus the typical value of the stolen data.
7. IEEE 802.11 is currently working on extensions to WEP for incorporation within a future version of the standard. This work was initiated in July 1999 as Task Group E, with the specific goal of strengthening the security mechanisms so as to provide a level of security beyond the initial requirements for Wired Equivalent Privacy. The enhancements currently proposed are intended to counter extremely sophisticated attacks, including those that have been recently reported on in the press. In addition it needs to be noted that the choice of encryption algorithms by IEEE 802.11 are not purely technical decisions but they are limited by government export law restrictions as well.
8. Certain reports in the press have implied that frequency hopping wireless LAN systems would be less vulnerable to security attacks than other wireless LANs. This is not true given that in such frequency hopping systems the hopping codes and timings are unencrypted and consequently are easily available to an attacker.
9. By far the biggest threat to the security of any wireless LAN is the failure to use the protection mechanisms that are available, including WEP. Any IEEE 802.11 installation where data privacy is a concern should use WEP.
I would like to thank the following long serving members of the IEEE 802.11 Working Group, and those Wireless Ethernet Compatibility Alliance members, for their efforts in assisting me in drafting this response from the Chair to this important issue:
Vic Hayes, IEEE 802.11 member & ex-IEEE 802.11 Chair Al Petrick, IEEE 802.11 WG Vice-Chair Harry Worstell, IEEE 802.11 WG Vice Chair John Fakatselis, IEEE 802.11 Task Group E Chair & TGE QoS Sub-Group Chair Dave Halasz, IEEE 802.11 TGE Security Sub-Group Chair Matthew Shoemake, IEEE 802.11 Task Group G Chair Phil Belanger, WECA Chairman & IEEE 802.11 member Greg Ennis, WECA Technical Director & IEEE 802.11 member.
Stuart J. Kerry
Chair, IEEE 802.11 , Standards Working Group for Wireless Local Area Networks.