Wireless Security Flawed, Researchers Report

Wireless devices, including laptop computers and PDAs that are widely used to access company networks, rely on a protocol that has "major security flaws" and are vulnerable to hackers using equipment they can obtain easily, a research group at the University of California at Berkeley has concluded.

The culprit is the Wired Equivalent Privacy (WEP) protocol used in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 international standard for wireless LAN communications. It has flaws that "seriously undermine the security claims of the system," leaving it vulnerable to attacks that decrypt traffic, researchers find. The research group intercepted wireless transmissions, modified transmissions, and accessed restricted networks in its examination.

The Internet Security, Applications, Authentication and Cryptography (ISAAC) researchers, a group in the university's computer science department, have published their findings. They say they hope IEEE will redesign the protocol, and that companies will design and implement networks with better security principles.

Changes in the Works

Vendors are quick to downplay the decryption achieved by the university group and say a task force within the IEEE 802.11 group is already working on encryption improvements.

"The paper underestimates how difficult it is to decrypt messages or access a system that uses WEP," says John Drewry, senior director of business development in the wireless connectivity division at 3Com, which is a member of the IEEE 802.11 group and a founding member of the Wireless Ethernet Compatibility Alliance. "These were sophisticated users using fairly sophisticated systems."

Nonetheless, Drewry adds, "WEP is an area the industry has been working on for some time. It was part of the original 802.11 specification in 1997 and even then everyone realized there needed to be some improvements."

Because wireless networks use shared radio waves to transmit data, they are particularly vulnerable to security breaches, which is why the 802.11 standard and WEP were created.

Easy to Uncover

The flaws exposed by the group make it possible--if not always easy--to intercept and decrypt wireless traffic from notebooks or PDAs using the 802.11 standard.

Hundreds of products employ the standard, which is meant to make wireless transmissions as safe as using a wired network by encrypting wireless traffic and using WEP to authenticate nodes. The flaws make proprietary wireless technologies like AirPort, developed by Apple and Lucent, vulnerable and leave those systems that rely on network base stations open for attack.

"Our analysis suggests that all of these attacks (outlined in the summary of findings) are practical to mount using only inexpensive off-the-shelf equipment," the researchers say in their report. "We recommend that anyone using an 802.11 wireless network not rely on WEP for security, and employ other security measures to protect their wireless network."

The research group needed only a wireless Ethernet interface that was subverted "to monitor and transmit encrypted data" by simply modifying driver settings. More difficult "active" attacks can be undertaken through reverse-engineering using products from companies that allow upgrading. The research group specifically cited Orinoco PC cards from Lucent.

"The time investment required is non-trivial; however, it is a one-time effort--the rogue firmware can then be posted on a Web site or distributed amongst underground circles," according to a draft of "Intercepting Mobile Communications: The Insecurity of 802.11," published on the ISAAC site. Authors of the report are two computer science graduate students, an associate professor, and an assistant professor.

Better Encryption Urged

Not even 128-bit encryption versions of WEP are secure, according to the paper, which spells out in detail how WEP works and how it can be subverted.

Many 802.11 vendors offer both 40-bit encryption (specified in the WEP standard) and 128- bit encryption, Drewry says. a??Companies like 3Com have also added Layer 3 and other security measures.a??

The IEEE group is looking to enhance 802.11a??s security mechanism through layered encryption, 3Coma??s Drewry says. a??3Com recognized this in July, and added Layer 3 security on top of WEP.a??

The ISAAC researchers suggest keeping the wireless network outside a company's firewall, as well as recommending other measures by network administrators to protect wireless networks.

They suggest controlling access by configuring the network so "no routes to the outside Internet exist from the wireless network. This prevents people within radio range of the wireless infrastructure from usurping potentially costly Internet connection bandwidth, requiring a virtual private network use for any outside access."

The group also recommends improving the encryption key management of wireless networks. "If possible, every host should have its own encryption key, and keys should be changed with high frequency," they suggest. However, they note that good key management alone does not protect wireless networks from all potential attacks.

3Com agrees with these suggestions, and says it already runs VPNs over the wireless network. Drewry also points out that secure wireless LANs depend on both the manufacturer and the staff who implements the network.

"One recommendation we offer is to put the wireless network on a separate subnet than the rest of the wireline network and to put a firewall in between them," Drewry says.

As for the IEEE enhancements to 802.11 security, Drewry says we can expect them later this year, probably before products appear for 802.11a, the next generation of 802.11.

Cameron Crouch of PCWorld.com contributed to this report.