CWAP-404 Online Practice Questions and Answers

Correct Answer: B

Explanation: Two frames are exchanged for 802.11 authentication in the 6 GHz band when WPA3-Enterprise is not used, and a passphrase is used instead. Authentication is a process that establishes an identity relationship between a STA (station) and an AP (access point) before joining a BSS (Basic Service Set). There are two types of authentication methods defined by 802.11: Open System Authentication and Shared Key Authentication. Open System Authentication does not require any credentials or security information from a STA to join a BSS, and it consists of two frames: an Authentication Request frame sent by the STA to the AP, and an Authentication Response frame sent by the AP to the STA. Shared Key Authentication requires a shared secret key from a STA to join a BSS, and it consists of four frames: two challenge-response frames in addition to the request-response frames. However, Shared Key Authentication uses WEP (Wired Equivalent Privacy) as its encryption algorithm, which is insecure and deprecated. In the 6 GHz band, which is a newly available frequency band for WLANs, Shared Key Authentication is prohibited by the 802.11 standard, as it poses security and interference risks for other users and services in the band. The 6 GHz band requires all WLANs to use WPA3-Personal or WPA3-Enterprise encryption methods, which are more secure and robust than previous encryption methods such as WPA2 or WEP. WPA3-Personal uses a passphrase to derive a PMK (Pairwise Master Key), while WPA3-Enterprise uses an authentication server to obtain a PMK. Both methods use SAE (Simultaneous Authentication of Equals) as their authentication protocol, which replaces PSK (Pre-Shared Key) or EAP (Extensible Authentication Protocol). SAE consists of two frames: an SAE Commit frame sent by both parties to exchange elliptic curve parameters and nonces, and an SAE Confirm frame sent by both parties to verify each other's identities and generate a PMK. Therefore, when WPA3-Enterprise is not used, and a passphrase is used instead in the 6 GHz band, only two frames are exchanged for 802.11 authentication: an SAECommit frame and an SAE Confirm frame. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 8: Security Analysis, page 220-221

Correct Answer: A

Explanation: The configured Minimum Basic Rate (MBR) of a BSS can be identified by looking at the Supported Rates and Extended Supported Rates elements in a Beacon frame. A Beacon frame is a type of management frame that is transmitted by an AP to advertise its presence and capabilities to potential clients. A Beacon frame contains various information elements (IEs) that provide details about the BSS configuration and operation. The Supported Rates andExtended Supported Rates IEs list the data rates that are supported by the AP for data transmission. The MBR is the lowest data rate among these supported rates that is required for all clients to join and communicate with the BSS. The MBR is usually marked with a flag bit in these IEs to indicate its mandatory status. The other options are not correct, as they do not exist or do not indicate the MBR of a BSS. References: [Wireless Analysis Professional Study Guide CWAP404], Chapter 5:

802.11 MAC Sublayer, page 123-124

Correct Answer: D

Explanation: The STA is discovering a list of available BSSs by sending a Probe Request with an empty SSID element. This is also known as a broadcast Probe Request, as it does not specify any particular SSID to probe for. Any AP that receives this Probe Request will respond with a Probe Response containing its own SSID and other information about its BSS. This way, the STA can learn about all the BSSs in its vicinity and choose which one to associate with . References: CWAP-404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter 6: MAC Sublayer Frame Exchanges, page 191; CWAP-404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter

6: MAC Sublayer Frame Exchanges, page 193.

Correct Answer: D

Explanation: The PHY layer provides framing by adding a header to create a PPDU. A PPDU (PHY Protocol Data Unit) is the data unit that is transmitted or received over the wireless medium by the PHY layer. A PPDU consists of a PSDU (PHY Service Data Unit) and a PHY header, which contains information such as modulation, coding, and data rate. The PHY layer adds the PHY header to the PSDU to create a PPDU for transmission, or removes the PHY header from the PPDU to extract the PSDU for reception. The other options are not correct, as they are not created by adding a header at the PHY layer. An MPDU (MAC Protocol Data Unit) is created by adding a MAC header and FCS to an MSDU (MAC Service Data Unit) at the MAC layer. An MSDU is the data unit that is passed from the LLC sublayer to the MAC sublayer or vice versa. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 4: 802.11 Physical Layer, page 97-98

Correct Answer: A

Explanation: All data frames will be retransmitted in this scenario. This is because the AP uses a Block Ack (BA) mechanism to acknowledge the receipt of multiple data frames from a client in a single frame. The BA contains a bitmap that indicates which data frames were received correctly and which were not. If the BA is not received by the AP due to frame corruption, the AP will assume that none of the data frames were received by the client and will retransmit all of them. The other options are not correct, as they do not account for the loss of the BA or the use of the bitmap. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 6: 802.11 Frame Exchanges, page 167-168

Correct Answer: B

Explanation: The Group Key Handshake consists of two frames excluding any Ack frames that may be required. The Group Key Handshake is used to distribute and update the Group Temporal Key (GTK) for encrypting broadcast and multicast traffic. The AP initiates the Group Key Handshake by sending a Group Key Message 1 frame to a STA, which contains the new GTK and other information. The STA responds with a Group Key Message 2 frame to the AP, which confirms the receipt of the GTK and other information. After this, both the AP and the STA can use the new GTK for encryption and decryption of broadcast and multicast traffic . References: CWAP-404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter 7: 802.11 Security, page 246; CWAP- 404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter 7:

802.11 Security, page 247.

Correct Answer: D

Explanation: The most likely issue that can be identified from the spectrum analysis is a power mismatch between the APs and the clients. A power mismatch occurs when the APs transmit at a higher power level than the clients, or vice versa. This can cause asymmetric communication, where one side can hear the other, but not vice versa. This can result in poor performance, disconnections, or packet loss. A spectrum analysis can reveal a power mismatch by showing different signal amplitudes or RSSI values for the APs and the clients on the same channel or frequency. The other options are not correct, as they cannot be identified from the spectrum analysis alone. The tablets' SSID, power save mode,

and noise floor can be determined by using other tools or methods, such as protocol analysis, site survey, or device configuration. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 3: Spectrum Analysis, page

Correct Answer: A

Explanation: An RTS (Request to Send) frame should be acknowledged by a CTS (Clear to Send) frame. An RTS and CTS frame are types of control frames that are used to implement a virtual carrier sense mechanism called RTS/CTS. RTS/CTS is a technique that helps to avoid collisions and hidden node problems in wireless transmissions. When a STA (station) wants to send a data frame, it first sends an RTS frame to the intended receiver, indicating the duration of the transmission. The receiver then responds with a CTS frame, also indicating the duration of the transmission. The other STAs in the vicinity hear either the RTS or the CTS frame and update their NAV (Network Allocation Vector) timers accordingly, deferring their access to the medium until the transmission is over. The sender then sends the data frame, followed by an ACK (Acknowledgement) frame from the receiver. The other options are not correct, as they are not used to acknowledge an RTS frame. An ACK frame is used to acknowledge a data frame, not an RTS frame. An RTS- Ack frame does not exist, as there is no such type of control frame in 802.11. A Block Ack (BA) frame is used to acknowledge multiple data frames in a single frame, not an RTS frame. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 6:

802.11 Frame Exchanges, page 166-167

Correct Answer: A

Explanation: Real-time packet decodes are not a consideration when configuring a long- term, forensic packet capture and saving all packets to disk. Real-time packet decodes are useful for live analysis and troubleshooting, but they consume CPU and memory resources that could affect the performance of the capture process. For a long-term, forensic packet capture, it is more important to consider the analyzer location, the total capture storage space, and the individual trace file size. These factors affect the quality and quantity of the captured packets and the ease of post-capture analysis34 References: CWAP-404 Study Guide, Chapter 2: Protocol Analysis, page 49 CWAP-404 Objectives, Section 2.1: Configure protocol analyzers

Correct Answer: D

Explanation: The difference between a Data frame and a QoS-Data frame is that QoS Data frames include a QoS control field. A Data frame is a type of data frame that is used to carry user data or upper layer protocol data between STAs and APs. A QoS Data frame is a type of data frame that is used to carry user data or upper layer protocol data between STAs and APs that support QoS (Quality of Service) features. QoS features allow different types of traffic to be prioritized and handled differently according to their QoS requirements, such as delay, jitter, throughput, etc. QoS Data frames include a QoS control field in their MAC header, which contains information such as traffic identifier (TID), queue size (TXOP), acknowledgment policy (ACK), etc., that are used for QoS purposes. The other options are not correct, as they do not describe the difference between Data and QoS Data frames. QoS Data frames do not include a DSCP (Differentiated Services Code Point) control field, which is part of the IP header in the network layer, not the MAC header in the data link layer. QoS Data frames do not include a QoS information element (IE), which is part of some management frames that indicate QoS capabilities or parameters, not data frames. QoS Data frames do not include an 802.1Q VLAN tag, which is part of some Ethernet frames that indicate VLAN membership or priority, not wireless frames. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 5:

802.11 MAC Sublayer, page 118-119