Given the following list of corporate access points, which of the following attacks is MOST likely underway if the company wireless network uses the same wireless hardware throughout? MACSID 00:01:AB:FA:CD:34Corporate AP 00:01:AB:FA:CD:35Corporate AP 00:01:AB:FA:CD:36Corporate AP 00:01:AB:FA:CD:37Corporate AP 00:01:AB:FA:CD:34Corporate AP
A. Packet sniffing B. Evil Twin C. WPS attack D. Rogue access point
Which of the following types of attacks involves interception of authentication traffic in an attempt to gain unauthorized access to a wireless network?
A. Near field communication B. IV attack C. Evil twin D. Replay attack
Explanation: An initialization vector is a random number used in combination with a secret key as a means to encrypt data. This number is sometimes referred to as a nonce, or “number occurring once,” as an encryption program uses it only once per session. An initialization vector is used to avoid repetition during the data encryption process, making it impossible for hackers who use dictionary attack to decrypt the exchanged encrypted message by discovering a pattern. This is known as an IV attack. A particular binary sequence may be repeated more than once in a message, and the more it appears, the more the encryption method is discoverable. For example if a one-letter word exists in a message, it may be either “a” or “I” but it can’t be “e” because the word “e” is non-sensical in English, while “a” has a meaning and “I” has a meaning. Repeating the words and letters makes it possible for software to apply a dictionary and discover the binary sequence corresponding to each letter. Using an initialization vector changes the binary sequence corresponding to each letter, enabling the letter “a” to be represented by a particular sequence in the first instance, and then represented by a completely different binary sequence in the second instance.
WEP (Wireless Equivalent Privacy) is vulnerable to an IV attack. Because RC4 is a stream cipher, the same traffic key must never be used twice. The purpose of an IV, which is transmitted as plain text, is to prevent any repetition, but a 24-bit IV is not long enough to ensure this on a busy network. The way the IV was used also opened WEP to a related key attack. For a 24-bit IV, there is a 50% probability the same IV will repeat after 5000 packets.
An administrator needs to secure a wireless network and restrict access based on the hardware address of the device. Which of the following solutions should be implemented?
A. Use a stateful firewall B. Enable MAC filtering C. Upgrade to WPA2 encryption D. Force the WAP to use channel 1
Explanation: MAC addresses are also known as an Ethernet hardware address (EHA), hardware address or physical address. Enabling MAC filtering would allow for a WAP to restrict or allow access based on the hardware address of the device.
Which of the following is an important implementation consideration when deploying a wireless network that uses a shared password?
A. Authentication server B. Server certificate C. Key length D. EAP method
Explanation: Key length is the main issue of concern since the wireless network uses a shared password. With risks of shared passwords makes the length of the password a crucial factor to risk mitigation.
The system administrator has been notified that many users are having difficulty connecting to the company’s wireless network. They take a new laptop and physically go to the access point and connect with no problems. Which of the following would be the MOST likely cause?
A. The certificate used to authenticate users has been compromised and revoked. B. Multiple war drivers in the parking lot have exhausted all available IPs from the pool to deny access. C. An attacker has gained access to the access point and has changed the encryption keys. D. An unauthorized access point has been configured to operate on the same channel.
Explanation: Wireless Access Points can be configured to use a channel. If you have multiple access points within range of each other, you should configure the access points to use different channels. Different channels use different frequencies. If you have two access points using the same channel, their Wi-Fi signals will interfere with each other. The question states that that many users are having difficulty connecting to the company’s wireless network. This is probably due to the signal being weakened by interference from another access point using the same channel. When the administrator takes a new laptop and physically goes to the access point and connects with no problems, he is able to connect because he is near the access point and therefore has a strong signal.
A retail store uses a wireless network for its employees to access inventory from anywhere in the store. Due to concerns regarding the aging wireless network, the store manager has brought in a consultant to harden the network. During the site survey, the consultant discovers that the network was using WEP encryption. Which of the following would be the BEST course of action for the consultant to recommend?
A. Replace the unidirectional antenna at the front of the store with an omni-directional antenna. B. Change the encryption used so that the encryption protocol is CCMP-based. C. Disable the network’s SSID and configure the router to only access store devices based on MAC addresses. D. Increase the access point’s encryption from WEP to WPA TKIP.
Explanation: CCMP is the standard encryption protocol for use with the WPA2 standard and is much more secure than the WEP protocol and TKIP protocol of WPA. CCMP provides the following security services: Data confidentiality; ensures only authorized parties can access the information Authentication; provides proof of genuineness of the user Access control in conjunction with layer management
A: The antenna type deals with signal strength and direction. It will not have a bearing on whether technology is older.
C: This option would “cloak” the network, not harden the network.
D: WPA2, which uses CCMP as its standard encryption protocol, more secure than WPA-TKIP.
Reference: http://en.wikipedia.org/wiki/CCMP http://en.wikipedia.org/wiki/Wi-Fi_Protected_Access Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 61, 63
Which of the following is a step in deploying a WPA2-Enterprise wireless network?
A. Install a token on the authentication server B. Install a DHCP server on the authentication server C. Install an encryption key on the authentication server D. Install a digital certificate on the authentication server
Explanation: When setting up a wireless network, you’ll find two very different modes of Wi-Fi Protected Access (WPA) security, which apply to both the WPA and WPA2 versions. The easiest to setup is the Personal mode, technically called the Pre-Shared Key (PSK) mode. It doesn’t require anything beyond the wireless router or access points (APs) and uses a single passphrase or password for all users/devices. The other is the Enterprise mode —which should be used by businesses and organizations—and is also known as the RADIUS, 802.1X, 802.11i, or EAP mode. It provides better security and key management, and supports other enterprise-type functionality, such as VLANs and NAP. However, it requires an external authentication server, called a Remote Authentication Dial In User Service (RADIUS) server to handle the 802.1X authentication of users.
To help you better understand the process of setting up WPA/WPA2-Enterprise and 802.1X, here’s the basic overall steps: Choose, install, and configure a RADIUS server, or use a hosted service.
Create a certificate authority (CA), so you can issue and install a digital certificate onto the RADIUS server, which may be done as a part of the RADIUS server installation and configuration. Alternatively, you could purchase a digital certificate from a public CA, such as GoDaddy or Verisign, so you don’t have to install the server certificate on all the clients. If using EAP-TLS, you’d also create digital certificates for each end-user. On the server, populate the RADIUS client database with the IP address and shared secret for each AP. On the server, populate user data with usernames and passwords for each end-user. On each AP, configure the security for WPA/WPA2-Enterprise and input the RADIUS server IP address and the shared secret you created for that particular AP. On each Wi-Fi computer and device, configure the security for WPA/WPA2-Enterprise and set the 802.1X authentication settings.
On Monday, all company employees report being unable to connect to the corporate wireless network, which uses 802.1x with PEAP. A technician verifies that no configuration changes were made to the wireless network and its supporting infrastructure, and that there are no outages. Which of the following is the MOST likely cause for this issue?
A. Too many incorrect authentication attempts have caused users to be temporarily disabled. B. The DNS server is overwhelmed with connections and is unable to respond to queries. C. The company IDS detected a wireless attack and disabled the wireless network. D. The Remote Authentication Dial-In User Service server certificate has expired.
Explanation: The question states that the network uses 802.1x with PEAP. The 802.1x authentication server is typically an EAP-compliant Remote Access Dial-In User Service (RADIUS). A RADIUS server will be configured with a digital certificate. When a digital certificate is created, an expiration period is configured by the Certificate Authority (CA). The expiration period is commonly one or two years. The question states that no configuration changes have been made so it’s likely that the certificate has expired.
A technician is investigating intermittent switch degradation. The issue only seems to occur when the building’s roof air conditioning system runs. Which of the following would reduce the connectivity issues?
A. Adding a heat deflector B. Redundant HVAC systems C. Shielding D. Add a wireless network
Explanation: EMI can cause circuit overload, spikes, or even electrical component failure. In the question it is mentioned that switch degradation occurs when the building’s roof air-conditioning system is also running. All electromechanical systems emanate EMI. Thus you could alleviate the problem using EMI shielding.
A security administrator has been tasked with setting up a new internal wireless network that must use end to end TLS. Which of the following may be used to meet this objective?
A. WPA B. HTTPS C. WEP D. WPA 2
Explanation: Wi-Fi Protected Access 2 (WPA2) was intended to provide security that’s equivalent to that on a wired network, and it implements elements of the 802.11i standard. In April 2010, the Wi-Fi Alliance announced the inclusion of additional Extensible Authentication Protocol (EAP) types to its certification programs for WPA- and WPA2- Enterprise certification programs. EAP-TLS is included in this certification program. Note: Although WPA mandates the use of TKIP, WPA2 requires Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP). CCMP uses 128-bit AES encryption with a 48-bit initialization vector. With the larger initialization vector, it increases the difficulty in cracking and minimizes the risk of a replay attack.