HPE6-A84 Aruba Certified Network Security Expert Written Exam Question and Answers

To configure user-based tunneling (UBT) on an AOS-CX switch, you need to specify the IP addresses of the mobility gateways that will receive the tunneled traffic from the switch 1. The primary controller is the preferred gateway for the switch to establish a tunnel, and the backup controller is the alternative gateway in case the primary controller fails or becomes unreachable 1. The IP addresses of the gateways should be their system IP addresses, which are used for inter-controller communication and cluster discovery 2.

In this scenario, the customer has a gateway cluster with two gateways, each with a system IP address on VLAN 4085. Therefore, the switch should use these system IP addresses as the primary and backup controllers for UBT. The IP addresses of the gateways on VLAN 20 and VLAN 4094 are not relevant for UBT, as they are used for user traffic and WAN connectivity, respectively 2. The VRRP IP address on VLAN 20 is also not applicable for UBT, as it is a virtual IP address that is not associated with any specific gateway 3.

Therefore, the best option is to use 10.20.4.21 as the primary controller and 10.20.4.22 as the backup controller for UBT on the switch. This will ensure high availability and cluster discovery for the tunneled traffic from the switch to the gateway cluster 12.

An authentication source is a configuration element in CPPM that defines how to connect to an external identity provider and retrieve user or device information . CPPM supports various types of authentication sources, such as Active Directory, LDAP, SQL, Kerberos, and HTTP .

To authenticate wireless and wired clients to Azure AD, you need to set up an authentication source as HTTP type, referencing Azure AD’s FQDN . This type of authentication source allows CPPM to use REST API calls to communicate with Azure AD and validate the user or device credentials . You also need to configure the OAuth 2.0 settings for the authentication source, such as the client ID, client secret, token URL, and resource URL .

To use information collected by Intune to make access control decisions, you need to set up another authentication source as HTTP type, referencing the Intune extension . This type of authentication source allows CPPM to use REST API calls to communicate with Intune and retrieve the device compliance status . You also need to configure the OAuth 2.0 settings for the authentication source, such as the client ID, client secret, token URL, and resource URL .

This is because SNMPv3 is a secure version of SNMP that provides authentication, encryption, and access control for network management. SNMPv3-only is a configuration option on AOS-CX switches that disables SNMPv1 and SNMPv2c, which are insecure versions of SNMP that use plain text community strings for authentication. By setting the snmp-server settings to “snmpv3-only”, the switch will only respond to SNMPv3 requests and reject any SNMPv1 or SNMPv2c requests, thus remedying the vulnerability and meeting the customer’s requirements.

A. Enabling control plane policing to automatically drop SNMP GET requests. This is not a valid recommendation because control plane policing is a feature that protects the switch from denial-of-service (DoS) attacks by limiting the rate of traffic sent to the CPU. Control plane policing does not disable SNMPv1 or SNMPv2c, but rather applies a rate limit to all SNMP requests, regardless of the version. Moreover, control plane policing might also drop legitimate SNMP requests if they exceed the rate limit, which could affect the network management.

C. Adding an SNMP community with a long random name. This is not a valid recommendation because an SNMP community is a shared secret that acts as a password for accessing network devices using SNMPv1 or SNMPv2c. Adding an SNMP community with a long random name does not disable SNMPv1 or SNMPv2c, but rather creates another community string that can be used for authentication. Moreover, adding an SNMP community with a long random name does not improve the security of SNMPv1 or SNMPv2c, as the community string is still transmitted in plain text and can be intercepted by an attacker.

D. Enabling SNMPv3, which implicitly disables SNMPv1/v2. This is not a valid recommendation because enabling SNMPv3 does not implicitly disable SNMPv1 or SNMPv2c on AOS-CX switches. Enabling SNMPv3 only adds support for the secure version of SNMP, but does not remove support for the insecure versions. Therefore, enabling SNMPv3 alone does not remedy the vulnerability or meet the customer’s requirements.

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.

MPSK (Multi Pre-Shared Key) is a feature that allows assigning different pre-shared keys (PSKs) to different devices or groups of devices on the same WLAN. MPSK improves security over WPA2 in personal mode, which uses a single PSK for all devices on the WLAN. With MPSK, you can create and manage multiple PSKs, each with its own role, policy, and expiration date. You can also revoke or change a PSK for a specific device or group without affecting other devices on the WLAN. MPSK is compatible with devices that support WPA2 in personal mode only, as they do not need to support any additional protocols or certificates.

To use MPSK on the WLAN to which the devices connect, you need to enable MPSK in the WLAN settings and configure the PSKs in Aruba ClearPass Policy Manager (CPPM). You can find more information about how to configure MPSK in the [Configuring Multi Pre-Shared Key - Aruba] page and the [ClearPass Policy Manager User Guide] . The other options are not correct because they either do not improve security or are not applicable for devices that support WPA2 in personal mode only. For example, configuring WIDS policies that apply extra monitoring to these particular devices would not prevent them from being compromised or spoofed, but rather detect and mitigate potential attacks. Connecting these devices to the same WLAN to which 802.1X-capable clients connect, using MAC-Auth fallback, would not provide strong authentication or encryption, as MAC addresses can be easily spoofed or captured. Enabling dynamic authorization (RFC 3576) in the AAA profile for the devices would not affect the authentication process, but rather allow CPPM to change the attributes or status of a user session on the controller without requiring re-authentication.

According to the Aruba Cloud Authentication and Policy Overview1, Device Insight tags are stored in the Endpoint Repository and can be used as conditions within CPPM role mapping or enforcement policy rules. The rule condition type should be Endpoint, and the attribute should be Device Insight Tags. No extra authorization source is required for services that use policies with these rules. Therefore, option D is the correct answer.

Option A is incorrect because creating an HTTP authentication source to the Central API is not necessary to use Device Insight tags as conditions. Device Insight tags are already synchronized between Central and CPPM, and can be accessed from the Endpoint Repository.

Option B is incorrect because using the Application type for the rule conditions is not applicable to Device Insight tags. The Application type is used to match attributes from the Application Authentication source, which is used to integrate with third-party applications such as Microsoft Intune or Google G Suite.

Option C is incorrect because using the Endpoints Repository type for the rule conditions is not valid for Device Insight tags. The Endpoints Repository type is used to match attributes from the Endpoints Repository source, which is different from the Endpoint type. The Endpoints Repository source contains information about endpoints that are manually added or imported into CPPM, while the Endpoint type contains information about endpoints that are dynamically discovered and profiled by CPPM or Device Insight. Adding Endpoints Repository as a secondary authentication source for services that use policies with these rules is also unnecessary and redundant.

 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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Dynamic authorization is a feature that allows CPPM to send change of authorization (CoA) or disconnect messages to the MC to modify or terminate a user session based on certain conditions or events 1. Dynamic authorization uses the RFC 3576 protocol, which is an extension of the RADIUS protocol 2.

To enable dynamic authorization on the MC, you need to configure the IP address and UDP port of the CPPM server as the RFC 3576 server on the MC 3. The default UDP port for RFC 3576 is 3799, but it can be changed on the CPPM server . The MC and CPPM must use the same UDP port for dynamic authorization to work properly 3.

In this scenario, the MC is configured with the IP address of the CPPM server (10.47.47.8) as the RFC 3576 server, but it is using the default UDP port of 3799. However, according to the exhibit, the CPPM server is using a different UDP port of 1700 for dynamic authorization . This mismatch causes the CoA requests from CPPM to fail on the MC, as shown by the statistics .

To fix this issue, you need to change the UDP port in the MCs’ RFC 3576 server config to match the UDP port used by CPPM, which is 1700 in this case. Alternatively, you can change the UDP port in CPPM to match the default UDP port of 3799 on the MC. Either way, you need to ensure that both devices use the same UDP port for dynamic authorization 3 .

This is because a parameter is a variable that can be defined and modified by the user or the script, and can be used to customize the behavior and output of the NAE script. A parameter can be referred to by using the syntax self ^ramsfname], where ramsfname is the name of the parameter.

By defining a parameter for the value, the developer can make the NAE script more flexible and adaptable to different scenarios and switches. The parameter can be set to a default value, such as 10, but it can also be changed by the user or the script based on the network conditions and requirements. For example, the parameter can be adjusted dynamically based on the average or standard deviation of the number of rejects per hour, or based on the feedback from the user or other admins. This way, the NAE script can trigger an alert only when the number of rejects is truly unusual and not just arbitrary.

A. Checking one of the access switches’ RADIUS statistics and adding 10 to the number listed for rejects. This is not a good recommendation because it does not account for the variability and diversity of the network environment and switches. The number of rejects listed for one switch might not be representative or relevant for another switch, as different switches might have different traffic patterns, client types, RADIUS configurations, etc. Moreover, adding 10 to the number of rejects is an arbitrary and fixed value that might not reflect the actual threshold for triggering an alert.

B. Defining a baseline and referring to it for the value. This is not a bad recommendation, but it is not as good as defining a parameter. A baseline is a reference point that represents the normal or expected state of a network metric or performance indicator. A baseline can be used to compare and contrast the current network situation and detect any anomalies or deviations. However, a baseline might not be easy or accurate to define, as it might require historical data, statistical analysis, or expert judgment. Moreover, a baseline might not be stable or constant, as it might change over time due to network growth, evolution, or optimization.

C. Using 10 (per hour) as a good starting point for the value. This is not a good recommendation because it is an arbitrary and fixed value that might not reflect the actual threshold for triggering an alert. Using 10 (per hour) as the value might result in false positives or false negatives, depending on the network conditions and switches. For example, if the normal number of rejects per hour is 5, then using 10 as the value might trigger an alert too frequently and unnecessarily. On the other hand, if the normal number of rejects per hour is 15, then using 10 as the value might miss some important alerts and risks.

Auto-site clustering is a feature that allows gateways in the same site and group to form a cluster automatically. However, this mode does not support VRRP IP addresses, which are required for dynamic authorization (CoA) from ClearPass Policy Manager (CPPM) to the gateways. Dynamic authorization is a mechanism that allows CPPM to change the attributes or status of a client session on the gateways without requiring re-authentication. This is useful for applying policies, roles, or bandwidth limits based on various conditions. Without VRRP IP addresses, CPPM would not be able to send CoA messages to the correct gateway in case of a failover event, resulting in inconsistent or incorrect client behavior.

To enable VRRP IP addresses for dynamic authorization, you need to set up gateway clusters manually and assign a VRRP VLAN and a VRRP IP address to each cluster. This way, CPPM can use the VRRP IP address as the NAS IP address for RADIUS communications and CoA messages. The VRRP IP address will remain the same even if the active gateway in the cluster changes due to a failover event, ensuring seamless operations. You can find more information about how to set up gateway clusters manually and configure VRRP IP addresses in the Gateway Cluster Deployment - Aruba page and the ClearPass Policy Manager User Guide1.

 This is because an Endpoint Context Server (ECS) is a feature that allows ClearPass to receive contextual information from external sources, such as Aruba Central, and use it for policy enforcement and reporting. An ECS can be configured to point to the Aruba Central API and fetch data such as device type, category, OS, applications, traffic flows, etc.

An ECS can be used to communicate the information that an IoT client has used SSH to Aruba ClearPass Policy Manager (CPPM). The ECS can query the Aruba Central API and retrieve the network traffic flows of the wireless IoT devices that are categorized as “Raspberry Pi” clients. The ECS can then filter the traffic flows by the SSH protocol and send the relevant information to CPPM. CPPM can then use this information for policy decisions, such as allowing or denying SSH access, or triggering alerts or actions.

B. On CPPM enable Device Insight integration. This is not a valid step because Device Insight is a feature that allows ClearPass to discover, profile, and fingerprint devices on the network using deep packet inspection (DPI) and machine learning (ML). Device Insight does not communicate with Aruba Central or receive information from it. Moreover, Device Insight might not be able to detect SSH traffic on encrypted wireless IoT devices without decrypting it first.

C. On Central configure APs and gateways to use CPPM as the RADIUS accounting server. This is not a valid step because RADIUS accounting is a feature that allows network devices to send periodic updates about the status and activity of authenticated users or devices to a RADIUS server, such as CPPM. RADIUS accounting does not communicate with Aruba Central or receive information from it. Moreover, RADIUS accounting might not be able to capture SSH traffic on wireless IoT devices without inspecting it first.

D. On Central set up CPPM as a Webhook application. This is not a valid step because Webhook is a feature that allows Aruba Central to send notifications or events to external applications or services using HTTP requests. Webhook does not communicate with CPPM or send information to it. Moreover, Webhook might not be able to send SSH traffic information on wireless IoT devices without filtering it first.

According to the AOS-CX Switches Multiple Vulnerabilities1, one of the vulnerabilities (CVE-2021-41000) affects the SSH service on AOS-CX switches. This vulnerability allows an unauthenticated remote attacker to cause a denial-of-service condition on the switch by sending specially crafted SSH packets. The impact of this vulnerability is high, as it could result in a loss of management access and network disruption. Therefore, one recommendation to make is to create a control plane ACL to limit the sources that can access the switch with SSH. This way, the switch can filter out unwanted or malicious SSH traffic and reduce the risk of exploitation.