If you’re planning to take the SY0-501 version of the Security+ exam, you should understand different types of wireless attacks. This includes several known attacks against wireless networks such as an access point placed within a network without official authorization.
For example, can you answer this question?
Q. A coffee shop recently stopped broadcasting the SSID for their wireless network. Instead, paying customers can view it on their receipt and use it to connect to the coffee shop’s wireless network. Today, Lisa turned on her laptop computer and saw the SSID. Which of the following is the MOST likely reason why?
A. Rogue AP
B. Evil attacker
C. Jamming
D. Bluejacking
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation are available at the end of this post.
Rogue AP
A rogue access point (rogue AP) is an AP placed within a network without official authorization. It might be an employee who is bypassing security or installed by an attacker. If an employee installs a rogue AP, the chances are higher that this AP will not be managed properly, increasing vulnerabilities to the network.
Generically, you can think of a rogue as a scoundrel, a crook, or a villain. Clearly, if a rogue is a crook or villain, then rogue access points are not an administrator’s friend. You might also see them called counterfeit access points, which is also a clear indication they aren’t legitimate.
Attackers may connect a rogue access point to network devices in wireless closets that lack adequate physical security. This access point acts as a sniffer to capture traffic passing through the wired network device, and then broadcasts the traffic using the wireless capability of the AP. The attacker can then capture the exfiltrated data files while sitting in the parking lot. Data exfiltration is the unauthorized transfer of data from an organization to a location controlled by an attacker.
Additionally, attackers may be able to use the rogue access point to connect into the wired network. This works the same way that regular users can connect to a wired network via a wireless network. The difference is that the attacker configures all the security for the counterfeit access point and can use it for malicious purposes.
If you discover an unauthorized AP, you should disconnect it as quickly as possible. A basic first step to take when you discover any attack is to contain or isolate the threat. By simply unplugging the Ethernet cable, you can stop the unauthorized AP from capturing network traffic.
Evil Twin
An evil twin is a rogue access point with the same SSID as a legitimate access point. For example, many public places such as coffee shops, hotels, and airports include free Wi-Fi as a service. An attacker can set up an AP using the same SSID as the public Wi-Fi network, and many unsuspecting users will connect to this evil twin.
Once a user connects to an evil twin, wireless traffic goes through the evil twin instead of the legitimate AP. Often, the attacker presents bogus logon pages to users to capture usernames and passwords. Other times, they simply capture traffic from the connection, such as email or text typed into web page text boxes, and analyze it to detect sensitive information they can exploit.
Although it might sound complex to set up an evil twin, it’s rather easy. Attackers can configure a laptop that has a wireless access card as an AP. With it running, the attackers look just like any other user in a coffee shop or airport waiting area. They’ll have their laptop open and appear to be working (just like you perhaps), and you’ll have no idea they are trying to steal your credentials or other personal data that you send over the Internet via the evil twin. Similarly, attackers can set one up in a parking lot or another location close to an organization and try to trick employees or visitors.
Often, administrators will use wireless scanners to perform site surveys. In addition to detecting noise on frequency bands, they can also detect rogue APs, including evil twins. The site survey can help them identify the physical location of access points because the signal will get stronger as the administrator gets closer.
Misconfigured Access Points
One of the primary reasons that wireless attacks are successful is because APs are misconfigured. For example, if an AP is not using WPA2 with AES and CCMP, it is susceptible to many attacks. Similarly, if WPS is enabled on an AP, a WPS attack can discover the PIN in a few hours simply by guessing. After it discovers the PIN, it can discover the passphrase.
Although your wireless router might be a little different, you’ll still be able to see many of the typical configuration settings.
Remember this
Rogue access points are often used to capture and exfiltrate data. An evil twin is a rogue access point using the same SSID as a legitimate access point. A secure AP blocks unauthorized users, but a rogue access point provides access to unauthorized users.
Q. A coffee shop recently stopped broadcasting the SSID for their wireless network. Instead, paying customers can view it on their receipt and use it to connect to the coffee shop’s wireless network. Today, Lisa turned on her laptop computer and saw the SSID. Which of the following is the MOST likely reason why?
A. Rogue AP
B. Evil attacker
C. Jamming
D. Bluejacking
Answer is A. This describes a rogue access point (AP). More specifically, it is an evil twin, which is a rogue AP with the same SSID as a legitimate access point.
While the person setting up the rogue AP may be evil, a CompTIA question won’t ask you to evaluate the character of an attacker.
Jamming typically prevents anyone from connecting to a wireless network.
Bluejacking is related to Bluetooth, not wireless networks.
See Chapter 4 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide for more information on wireless attacks.