HPE6-A84 Practice Exam Questions with Answers Aruba Certified Network Security Expert Written Exam Certification

A DNS SAN (Subject Alternative Name) is an extension of the X.509 certificate standard that allows specifying additional hostnames or IP addresses that the certificate can be used for. A DNS SAN is useful for validating the identity of the server or client that presents the certificate, especially when the common name (CN) field does not match the hostname or IP address of the server or client.

In this case, the certificate has a CN of mc41.site94.example.com, which is the fully qualified domain name (FQDN) of the standalone Aruba Mobility Controller (MC). However, this CN may not match the hostname or IP address that the MC uses for the Web UI or for implementing RadSec with Aruba ClearPass Policy Manager. For example, if the MC uses a different FQDN, such as mc41.example.com, or an IP address, such as 192.168.1.41, for these purposes, then the certificate would not be valid for them. Therefore, the certificate should have a DNS SAN that includes all the possible hostnames or IP addresses that the MC may use for the Web UI and RadSec.

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.

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 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.

This option allows CPPM to receive real-time information about the network activity and security posture of the clients from the firewall, and then apply appropriate enforcement actions based on the configured policies 12. For example, if a client is detected to be infected with malware or violating the network usage policy, CPPM can quarantine or disconnect the client from the network 2.

The exhibit shows a screenshot of a certificate that has the following information:

• The subject common name (CN) is *.clearpass.local, which is a wildcard domain name that matches any subdomain under clearpass.local.
• The subject alternative names (SANs) are DNS Name=clearpass.local and DNS Name=*.clearpass.local, which are the same as the subject CN.
• The issuer CN is clearpass.local, which is the same as the subject domain name.
• The key usage (KU) is Digital Signature and Key Encipherment, which are required for RADIUS/EAP and RadSec usages.
• The extended key usage (EKU) is Server Authentication and Client Authentication, which are also required for RADIUS/EAP and RadSec usages.

The issue with this certificate is that it uses a fully qualified the ‘.local’ domain name, which is a reserved domain name for local networks that cannot be registered on the public Internet. This means that the certificate cannot be verified by any public certificate authority (CA), and therefore cannot be trusted by any external devices or servers that communicate with ClearPass. This could cause problems for RADIUS/EAP and RadSec usages, as they rely on secure and authenticated connections between ClearPass and other devices or servers.

To avoid this issue, the certificate should use a valid domain name that can be registered on the public Internet, such as clearpass.com or clearpass.net. This way, the certificate can be issued by a public CA that is trusted by most devices and servers, and can be verified by them. Alternatively, if the certificate is intended to be used only within a private network, it should be issued by a private CA that is trusted by all devices and servers within that network.

 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.

Aruba Central supports site-to-site VPNs between AOS 10 gateways, which are Aruba devices that provide routing, firewall, and VPN functions. Aruba Central can automatically provision and manage the site-to-site VPNs using the VPN Manager feature. The VPN Manager allows you to create VPN groups that consist of one or more hubs and branches, and define the VPN settings for each group1

Aruba Central uses IPsec as the protocol to secure the site-to-site connections between the AOS 10 gateways. IPsec is a standard protocol that provides encryption, authentication, and integrity for IP packets. Aruba Central automatically establishes IPsec tunnels for all site-to-site connections using keys that are securely distributed by Central. The keys are generated by Central and pushed to the gateways using a secure channel. The keys are rotated periodically to enhance security2

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 .

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

According to the AOS-CX User Guide, one way to configure the VLAN setting for the reception role is to assign a consistent name to VLAN 14, 24, or 34 on each access layer switch and reference that name in the enforcement profile VLAN settings. This way, the switches can download the role settings from CPPM and apply the correct VLAN based on the name, rather than the ID. For example, the enforcement profile VLAN settings could be:

And the VLAN configuration on each switch could be:

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 .

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.