Wireless IDSes Defend Your AirspaceBy Andrew Garcia | Posted 2004-08-07 Email Print
WLAN intrusion detection systems can help spot and lock out trouble in new ways.
eWEEK Labs advises every enterprise that is considering deployment of a wireless network or maintaining an existing one to seriously consider investing in a wireless intrusion detection system. A wide variety of these products stands ready to help identify and troubleshoot security and performance issues related to wireless technology.
However, based on our tests of a range of these solutions, we believe companies should carefully assess their wireless security needs because their existing infrastructure devices may already fulfill them.
Wireless IDS solutions range from handheld products that are designed for on-the-spot troubleshooting at a point in time, to capabilities integrated into existing access points and managing switches, to distributed fleets of sensors that provide round-the-clock coverage.
In tests, we've found that defensive overlay networks, such as those from AirMagnet Inc., AirDefense Inc. and Network Chemistry Inc., provide best-of-breed capabilities. Defensive overlay products enable a host of security and performance monitoring capabilities and have strong policy options that alert administrators to any signs of trouble.
Defensive overlay network vendors are rapidly adding features that not only alert but also can be configured to isolate and block wayward connections over the wire or over the air. These vendors also are increasingly tuning their products to use location findings to make policy decisions.
Despite recent reports of vulnerabilities in the RADIUS (Remote Authentication Dial-In User Service) authentication mechanism upon which 802.11i is based, 802.11i goes a long way toward equalizing the security of known, managed devices on wireless networks and on wired ones. 802.11i does so by delivering strong standards-compliant encryption via AES (Advanced Encryption Standard) and port-based 802.1x authentication to WLANs (wireless LANs).
However, many threats remain outside the scope of 802.11i, including access points and client nodes that are loosely maintained (or are completely outside IT's control). Poor configuration practices and unauthorized usage can lead to fundamental network headaches or nefarious intrusions.
The threat of rogue access points has been well-publicized. Employees installing their own unsecured access points on a corporate network leave a wide-open vector for LAN attacks that bypass network firewalls and wireless security measures implemented by IT.
But misconfigured and unsecured client devices also represent a significant threat. With the proliferation of WLAN hot spots and wireless devices in the home, users are leveraging their wireless connections in a multitude of locations. To ease migration between these disparate networks, WLAN client configurations are often left in a defaultand insecurestate. When first enabled, the clients probe constantly for open WLAN networks, often attaching to nearunknown access points without user knowledge or interaction.
Man-in-the-middle attacks exploit these circumstances. A simple sniff of the air can determine a client's network name and channel information, allowing a hacker to similarly configure a rogue access point. A spoofed deauthentication packet gets the wireless client to drop its association with its known access point, and the client can then associate with the rogue, allowing an intruder to potentially capture data and passwords. If bridging between the WLAN and Ethernet adapters is enabled on this client, the two networks are suddenly connected, bypassing network perimeter security.
In tests, eWEEK Labs has encountered interesting results from a misconfigured client bridging the internal wired network and an unknown wireless network. We've witnessed other wired clients receiving their DHCP (Dynamic Host Configuration Protocol) address from the remote wireless network's server. We've also seen the offending client used as a launching pad for attacks on the protected network.
Wireless IDS products must effectively patrol the airwaves for unknown access points and open client connections. Preferably, the solution should be able to determine whether a rogue is connected to the protected network or is simply occupying the same airspace, and it should also provide the granularity of policy definition to be able to define legitimate connections and be alert for those that aren't.
Next page: Hardware closes the gap.
In tests, eWEEK Labs found that distributed wireless overlay networks provide the most feature-rich products and comprehensive coverage, but infrastructure manufacturers such as Aruba Wireless Networks Inc. are quickly closing the gap with features integrated into their infrastructure access line of access points and WLAN switches.
To test the capabilities of intrusion detection engines, we invited AirMagnet, AirDefense and Highwall Technologies Ltd. to submit products. We found that each tested product capably detected our simulated attacks and rogue devices, but there were significant differences in the sensor devices and policy creation and notification tools.
There's a race among wireless IDS vendors to quickly add new features. We expect AirDefense and AirMagnet to offer significant feature upgrades within the next month. While the vendors will continue to enhance their detection and correlation routines, buyers should expect to see significant improvements in location tracking and radio-frequency jamming in future revisions.
Better location tracking is a particularly welcome development, since we've been less than impressed with early location results. In our tests, location tracking is generally accurate only to about 30 feet, leaving roughly 314 square feet of area or more for us to manually search.
One of the drawbacks with distributed wireless overlay solutions is that they require a separately managed overlay network, which means IT departments must deploy a fleet of sensors and face issues regarding power and network connectivity. And because many wireless networks are already deployed as an overlay to the wired infrastructure, these products can quickly lead to an out-of-control layering of the network.
As an alternative, wireless infrastructure products are quickly gaining wireless IDS capabilities. Because these products' sensor capabilities are integrated with a WLAN infrastructure, they allow greater flexibility to actively block suspicious connections via access blacklists and wireless DoS (denial-of-service) measures. If corporations are looking to replace early-generation wireless equipment to add 802.11i support, these products may well fit the bill for access and monitoring alike.
Access points from wireless switch vendors Airespace Inc. and Trapeze Networks Inc. periodically scan all the channels as part of their operating routine, which is fine for finding rogue access points but less effective for pinpointing attacks and keeping tabs on client activity. We fully expect that all enterprise-class access points will offer some level of rogue detection within a year. For instance, Cisco Systems Inc. has integrated limited rogue detection into its access points that is enhanced when used in conjunction with the company's Wireless LAN Solution Engine.
Aruba has taken things a step further, offering the most comprehensive IDS features among the infrastructure products we've seen. Aruba allows its access points to be configured as active access points that monitor a single channel or as sensors that sweep the spectrum.
Handheld or laptop-based solutions are also available. Although they provide only single-point-in-time data and are therefore inadequate for security monitoring, they can be invaluable for pinpointing the location of rogue access points to disable thema useful accessory when overlay or infrastructure location results leave a lot of room for error.
We've found AirMagnet's Laptop Trio to be the best solution in this class, but WildPackets Inc.'s AiroPeek NX and Network Instruments LLC's Observer 10 also perform well.
Technical Analyst Andrew Garcia can be reached at firstname.lastname@example.org.
Next page: Where to turn for help.
Where to turn for help
Numerous products are available to help administrators monitor and manage their radio environment, ranging from free-standing overlay defensive networks to single-point-in-time-and-space detection programs. The solutions listed below not only will detect rogue access points and clients but also can help administrators identify and troubleshoot interference, possible attacks and policy violations.
AirMagnet's Distributed Wireless Solution
Bluesocket Inc.'s BlueSecure Intrusion Protection System
Highwall's Rogue Detection System
Network Chemistry's RFprotect
Newbury Networks Inc.'s WiFi Watchdog