DNS tunneling is a technique that abuses the DNS protocol to tunnel data or commands between a compromised host and an attacker’s server. DNS tunneling can be used to establish a command and control channel, which allows the attacker to remotely control the malware or exfiltrate data from the infected host1

The traffic capture in the exhibit shows some signs of DNS tunneling. The source IP address is 10.1.7.2, which is likely an internal host behind a firewall. The destination IP address is 8.8.8.8, which is a public DNS resolver. The DNS queries are for subdomains of badsite.com, which is likely a malicious domain registered by the attacker. The subdomains have long and random names, such as 0x2a0x2a0x2a0x2a0x2a0x2a0x2a0x2a.badsite.com, which could be used to encode data or commands. The DNS responses have large sizes, such as 512 bytes, which could be used to carry data or commands back to the host2

A beacon is a type of network traffic that is sent from a compromised device to a command and control (C2) server, which is a remote system that controls the malicious activities of the device . A beacon is used to establish and maintain communication between the device and the C2 server, as well as to receive instructions or exfiltrate data .

A common characteristic of a beacon is that it is periodic, meaning that it is sent at regular intervals, such as every few minutes or hours . This helps the C2 server to monitor the status and availability of the device, as well as to avoid detection by network security tools .

Another common characteristic of a beacon is that it is small and identically sized, meaning that it contains minimal or fixed amount of data, such as a simple acknowledgment or a random string . This helps the device to conserve bandwidth and resources, as well as to avoid detection by network security tools .

 This is because this URI specifies the exact attribute that contains the number of access rejects from the RADIUS server, which is the information that the NAE script needs to monitor and trigger an alert.

A. /rest/v1/system/vrfs/mgmt/radius/servers/cp.acnsxtest.local/2083/tcp?attributes=authstatistics. This is not the correct URI because it returns the entire authstatistics object, which contains more information than the access rejects, such as access accepts, challenges, timeouts, etc. This might make the NAE script more complex and inefficient to parse and process the data.

B. /rest/v1/system/vrfs/mgmt/radius/servers/cp.acnsxtest.local/2083/tcp?attributes=authstatistics?attributes=access_rejects. This is not a valid URI because it has two question marks, which is a syntax error. The question mark is used to indicate the start of the query string, which can have one or more parameters separated by ampersands. The correct way to specify multiple attributes is to use a comma-separated list after the question mark, such as ?attributes=attr1,attr2,attr3.

C. /rest/v1/system/vrfs/mgmt/radius/_servers/cp.acnsxtest.local/2083/tcp. This is not a valid URI because it has an extra underscore before servers, which is a typo. The correct resource name is servers, not _servers. Moreover, this URI does not specify any attributes, which means it will return the default attributes of the RADIUS server object, such as name, port, protocol, etc., but not the authstatistics or access_rejects.

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Rules 6 and 7 in the “medical-mobile” policy are used to deny access to the WLAN for a period of time if the clients send any SSH or Telnet traffic, as required by the scenario. However, these rules are currently placed below rule 5, which permits access to the Internet for any traffic. This means that rule 5 will override rules 6 and 7, and the clients will not be denied access to the WLAN even if they send SSH or Telnet traffic.

To fix this issue, rules 6 and 7 should be moved to the top of the list, before rule 5. This way, rules 6 and 7 will take precedence over rule 5, and the clients will be denied access to the WLAN if they send SSH or Telnet traffic, as expected.

Alert duration and threshold settings are used to control how often and under what conditions email notifications are sent for gateway IDS/IPS events 1. By adjusting these settings, the customer can reduce the frequency of repeat email notifications for the same threat, while still being informed of any critical or new threats.

To adjust the alert duration and threshold settings in Aruba Central, the customer can follow these steps 1:

• In the Aruba Central app, set the filter to Global, a group, or a device.
• Under Analyze, click Alerts & Events.
• Click the Config icon to open the Alert Severities & Notifications page.
• Select the Gateway IDS/IPS tab to view the alert categories and severities for gateway IDS/IPS events.
• Click on an alert category to expand it and view the alert duration and threshold settings for each severity level.
• Enter a value in minutes for the alert duration. This is the time period during which the alert is active and email notifications are sent.
• Enter a value for the alert threshold. This is the number of times the alert must be triggered within the alert duration before an email notification is sent.
• Click Save.

By increasing the alert duration and/or threshold values, the customer can reduce the number of email notifications for recurring threats, as they will only be sent when the threshold is reached within the duration. For example, if the customer sets the alert duration to 60 minutes and the alert threshold to 10 for a Critical severity level, then an email notification will only be sent if the same threat occurs 10 times or more within an hour.

The correct answer is B. Create a new VLAN on the AOS-CX switch and configure that VLAN as the UBT client VLAN.

User-based tunneling (UBT) is a feature that allows the AOS-CX switches to tunnel the traffic from wired clients to a mobility gateway cluster, where they can be assigned a role and a VLAN based on their authentication and authorization 1. To enable UBT, the switches need to have a UBT zone configured with the IP addresses of the gateways, and a UBT client VLAN configured with the ubt-client-vlan command 2.

The UBT client VLAN is a special VLAN that is used to encapsulate the traffic from the tunneled clients before sending it to the gateways. The UBT client VLAN must be different from any other VLANs used on the switch or the network, and it must not be assigned to any ports or interfaces on the switch 2. The UBT client VLAN is only used internally by the switch for UBT, and it is not visible to the clients or the gateways.

In this scenario, the customer wants to tunnel the clients that pass user authentication to the gateway cluster, where they will be assigned to VLAN 20. Therefore, the switch must have a UBT client VLAN configured that is different from VLAN 20 or any other VLANs on the network. For example, the switch can use VLAN 4000 as the UBT client VLAN, as shown in one of the web search results 3. The switch must also have a UBT zone configured with the system IP addresses of the gateways as the primary and backup controllers, as explained in question 3.

The other options are not correct or relevant for this issue:

• Option A is not correct because assigning VLAN 20 as the access VLAN on any edge ports to which tunneled clients might connect would conflict with UBT. The access VLAN is the VLAN that is assigned to untagged traffic on a port, and it is used for local switching on the switch 4. If VLAN 20 is assigned as the access VLAN, then the traffic from the clients will not be tunneled to the gateways, but rather switched locally on VLAN 20. This would defeat the purpose of UBT and cause inconsistency in role and VLAN assignment.
• Option C is not correct because VIA licenses are not required for UBT. VIA licenses are required for enabling VPN services on Aruba Mobility Controllers for remote access clients using Aruba Virtual Intranet Access (VIA) software . VIA licenses are not related to UBT or wired clients.
• Option D is not correct because changing the port-access auth-mode mode to client-mode on any edge ports to which tunneled clients might connect would not affect UBT. The port-access auth-mode mode determines how a port handles authentication requests from multiple clients connected to a single port . Client-mode is the default mode that allows only one client per port, while multi-client-mode allows multiple clients per port. The port-access auth-mode mode does not affect how UBT works or how traffic is tunneled from a port.

AppRF and WebCC are features that allow the MCs to classify and control application traffic and web content based on predefined or custom categories 12. These features are required to meet the scenario requirements of denying access to all high-risk websites and denying access to the WLAN for a period of time if they send any SSH or Telnet traffic.

To enable AppRF and WebCC, you need to check the following settings:

• On the global level, you need to enable AppRF and WebCC under Configuration > Services > AppRF and Configuration > Services > WebCC, respectively 12.
• On the role level, you need to enable AppRF and WebCC under Configuration > Security > Access Control > Roles > medical-mobile > AppRF and Configuration > Security > Access Control > Roles > medical-mobile > WebCC, respectively 12.
• You also need to make sure that the MCs have valid licenses for AppRF and WebCC, which are included in the ArubaOS PEFNG license 3.