Q&A: Locking Down Wireless Networks

Md Sohail Ahmad, a senior wireless security researcher at AirTight Networks, which develops wireless security products, recently talked with Dr. Dobb's editor in chief Jon Erickson about the state of wireless security.

Dr. Dobb's: What's unique about wireless security?

Ahmad: Wireless brings a fundamental paradigm shift to security in that the network access and data transmission is now over the air, a shared and unbounded medium. Without appropriate security, it's very easy for an unauthorized user sitting in the parking lot outside your building or even few blocks away to steal your data in the air and similarly to gain access to your organization's network through the air. The Wi-Fi 802.11 protocol is an open standard; it operates in unlicensed frequency band; and hardware and software is available off the shelf incorporating it, which maximizes this risk. This risk is absent in wired networks.

Dr. Dobb's: What's the biggest wireless threat?

Ahmad: Wi-Fi access points are inexpensive and available off the shelf. Most portable computers like laptops and netbooks, as well as smartphones, such as the iPhone and BlackBerry, and consumer devices, like printers, come with Wi-Fi built in. These devices are flooding the enterprise, and, in turn, putting enterprise security into the hands of end users more than ever before. End users could inadvertently or maliciously put enterprise security at risk, for instance, by plugging in an unsecured Wi-Fi access point into the enterprise network or sharing their enterprise network access with outsiders over Wi-Fi. Unmanaged, unsecured Wi-Fi devices, the flood of Wi-Fi endpoints into the enterprise, and the lack of awareness among administrators and users about these vulnerabilities are the biggest wireless threats.

Dr. Dobb's: What's the biggest security mistake companies make?

Ahmad: As far as wireless security is concerned, the biggest mistake organizations make is to apply wired network security philosophy and solutions to implement wireless security. Network administrators often make the mistake of thinking that having solid wired security is enough to take care of Wi-Fi security risks. On the contrary, unsecured Wi-Fi attached to the enterprise network can open a back door for hackers to enter the wired enterprise network while completely bypassing all wired security measures such as firewalls, wired IDS/IPS, and content filters.

Dr. Dobb's: Are there emerging wireless security standards?

Ahmad: Given that Wi-Fi transmissions are over the air, the security of in-flight wireless data starts with strong encryption and authentication. The earliest Wi-Fi security protocol was the Wired Equivalent Privacy (WEP) protocol, which is now known to be broken; the latest is Wi-Fi Protected Access version 2 (WPA2), which uses the advanced encryption standard and 802.1x based authentication. While WPA2 has so far done its job in protecting Wi-Fi networks from outsiders, a flaw in the protocol that was recently demonstrated at BlackHat Arsenal 2010 and Defcon18 exposes WPA2-secured Wi-Fi networks to insider attacks.

Dr. Dobb's: How safe are airports for wireless users?

Ahmad: Airports are prime targets for Wi-Fi-based attacks. Most airport Wi-Fi hotspots use Open Wi-Fi, which is extremely insecure. Some hotspot providers are migrating to the WPA2 protocol for Wi-Fi security. Travelers should beware of WPA2's Hole196 vulnerability, which exposes the inherent lack of inter-user data privacy among authorized users of WPA2-secured Wi-Fi networks (see www.airtightnetworks.com/wpa2-hole196).

Dr. Dobb's: What's the easiest thing companies can do to enhance wireless security?

Ahmad: Like any security, there are no shortcuts to wireless security. Companies should follow some best practices to protect their networks from wireless vulnerabilities and threats:

>> Use WPA2 (AES and 802.1x) to secure your Wi-Fi network from outsiders.

>> Use a wireless intrusion prevention system to continuously monitor your airspace and proactively detect, block, and locate threat-posing Wi-Fi devices or those that may be violating your company's security policy.

>> Educate end users about risks from careless use of Wi-Fi on their endpoints on premises or on the road, such as at airports and coffee shops.