Hacking For Dummies, 4th Edition by Kevin Beaver CISSP

Author:Kevin Beaver, CISSP
Language: eng
Format: epub
Publisher: John Wiley and Sons, Inc.
Published: 2013-07-31T16:00:00+00:00

Chapter 9

Wireless LANs

In This Chapter

Understanding risks of wireless LANs

Selecting wireless LAN hacking tools

Cracking wireless encryption

Minimizing wireless LAN risks

Wireless local area networks (WLANs, also called Wi-Fi) — specifically, the ones based on the IEEE 802.11 standard — are increasingly being deployed into both business and home networks. WLANs have been the poster child for weak security and network hack attacks since the inception of 802.11 over a decade ago. The stigma of unsecure WLANs is starting to wane, but this isn’t the time to lower your defenses.

WLANs offer a ton of business value, from convenience to reduced network deployment time. Whether or not your organization allows wireless network access, you probably have it, so testing for WLAN security vulnerabilities is critical. In this chapter, I cover some common wireless network security vulnerabilities that you should test for, and I discuss some cheap and easy countermeasures that you can implement to help ensure that WLANs aren’t more of a risk to your organization than they’re worth.

Understanding the Implications of Wireless Network Vulnerabilities

WLANs are very susceptible to attack — even more so than wired networks (discussed in Chapter 8). Wireless networks have vulnerabilities that can allow an attacker to bring your network to its knees or allow your sensitive information to be extracted right out of thin air. If your WLAN is compromised, you can experience the following problems:

Loss of network access, including e-mail, web, and other services that can cause business downtime

Loss of sensitive information, including passwords, customer data, intellectual property, and more

Regulatory consequences and legal liabilities associated with unauthorized users gaining access to your business systems

Most of the wireless vulnerabilities are in the 802.11 standard and how it works. Wireless access points (APs) and client systems have some vulnerabilities as well.

Various fixes have come along in recent years to address these vulnerabilities, yet still many of these fixes haven’t been properly applied or aren’t enabled by default. Your employees might also install rogue WLAN equipment on your network without your knowledge. Then there’s “free” Wi-Fi practically everywhere your mobile workforce goes. These free Internet connections are one of the most serious threats to your overall information security and a pretty difficult one to fight. Even when WLANs are hardened and all the latest patches have been applied, you still might have security problems, such as DoS, man-in-the-middle attacks, and encryption key weaknesses (like you have on wired networks — see Chapter 8), that will likely be around for a while.

Choosing Your Tools

Several great WLAN security tools are available for both the Windows and UNIX platforms. The UNIX tools — which run mostly on Linux and BSD — were notoriously a bear to configure and run properly, but that problem has changed in recent years in programs such as Kismet (www.kismetwireless.net) and Wellenreiter (http://sourceforge.net/projects/wellenreiter).

If you want the power of the security tools that run on Linux, but you’re not interested in installing and learning much about Linux or don’t have the time to

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