Posture is a service in Cisco ISE that checks the compliance of endpoints with corporate security policies before allowing them to connect to the network. Posture policies define the requirements that endpoints must meet to be compliant, such as having antivirus software installed and updated, or having a specific registry key value. If an endpoint is compliant, Cisco ISE can apply a Change of Authorization (CoA) to grant it access to the network resources. CoA is a mechanism that allows Cisco ISE to dynamically change the authorization attributes of an existing session, such as VLAN, dACL, or SGT, without requiring the user to reauthenticate. CoA can be triggered by various events, such as posture assessment results, profiling changes, or manual actions by the administrator. CoA can also be used to quarantine or disconnect non-compliant endpoints. Therefore, ensuring that an endpoint is compliant with a posture policy configured in Cisco ISE provides the benefit of allowing CoA to be applied if the endpoint status is compliant. References :=
* Cisco Identity Services Engine Administrator Guide, Release 2.2 - Configure Client Posture Policies
* Cisco Identity Services Engine Administrator Guide, Release 2.2 - Change of Authorization

Multifactor authentication (MFA) is an authentication method that requires the user to provide two or more verification factors to gain access to a resource such as an application, online account, or a VPN1. MFA is a core component of a strong identity and access management (IAM) policy. MFA can help prevent an attacker from stealing usernames and passwords of users within an organization by adding an extra layer of security beyond the traditional username and password. For example, a user may need to enter a one-time code sent to their phone or email, scan their fingerprint, or use a hardware token to prove their identity. This way, even if an attacker obtains the user's credentials, they cannot access the resource without the second factor2.
The other options are not technologies that can help prevent an attacker from stealing usernames and passwords of users within an organization. RADIUS-based REAP is a protocol that allows wireless clients to authenticate with a RADIUS server, but it does not provide MFA3. Fingerprinting is a technique that identifies the operating system or application of a device based on its network characteristics, but it does not provide MFA4. Dynamic ARP Inspection is a security feature that prevents ARP spoofing attacks by validating ARP packets, but it does not provide MFA5.
References := 1: What is Multi-Factor Authentication (MFA)? |
OneLogin(https://www.onelogin.com/learn/what-is-mfa) 2: What is: Multifactor Authentication - Microsoft Support(https://support.microsoft.com/en-us/topic/what-is-multifactor-authentication-e5e39437-121c-be60-d123 Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 3: Securing the Network, Lesson 3.3: Secure Wireless Connectivity, Topic 3.3.1: Wireless Security Protocols, page 3-40. 4:
Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 2: Securing the Cloud, Lesson 2.2: Cloud Security Assessment, Topic 2.2.1: Cloud Security Concepts, page 2-13. 5: Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 3: Securing the Network, Lesson 3.2:
Secure Network Access, Topic 3.2.2: Layer 2 Security Features, page 3-19.

ExplanationPing of Death (PoD) is a type of Denial of Service (DoS) attack in which an attacker attempts to crash,destabilize, or freeze the targeted computer or service by sending malformed or oversized packets using a simple ping command.A correctly-formed ping packet is typically 56 bytes in size, or 64 bytes when the ICMP header is considered,and 84 including Internet Protocol version 4 header. However, any IPv4 packet (including pings) may be as large as 65,535 bytes. Some computer systems were never designed to properly handle a ping packet larger than the maximum packet size because it violates the Internet Protocol documentedLike other large but well-formed packets, a ping of death is fragmented into groups of 8 octets beforetransmission. However, when the target computer reassembles the malformed packet, a buffer overflow can occur, causing a system crash and potentially allowing the injection of malicious code.

Cisco Identity Services Engine (ISE) uses various probes to collect attributes of connected endpoints, such as device type, operating system, IP address, MAC address, and so on. These attributes are used to profile the endpoints and assign them to appropriate identity groups and policies. Two of the probes that can be configured to gather attributes of connected endpoints using Cisco ISE are RADIUS and DHCP.
* RADIUS probe: The RADIUS probe collects attributes from the RADIUS packets that are exchanged between the network access devices (NADs) and the ISE Policy Service Nodes (PSNs) during the
* authentication and authorization process. The RADIUS probe can extract attributes such as username, calling-station-ID, NAS-IP-address, NAS-port-type, service-type, and so on. The RADIUS probe can also collect attributes from the RADIUS accounting packets that are sent by the NADs to the ISE PSNs after the session is established. The RADIUS probe can extract attributes such as session-ID, framed-IP-address, acct-session-time, and so on. The RADIUS probe is enabled by default and does not require any additional configuration on the NADs or the ISE PSNs.
* DHCP probe: The DHCP probe collects attributes from the DHCP packets that are exchanged between the endpoints and the DHCP server during the IP address assignment process. The DHCP probe can extract attributes such as hostname, vendor-class-identifier, client-identifier, parameter-request-list, and so on. The DHCP probe can also collect attributes from the DHCP relay packets that are forwarded by the NADs to the ISE PSNs. The DHCP probe can extract attributes such as relay-agent-information and subscriber-ID. The DHCP probe requires some configuration on the NADs and the ISE PSNs. The NADs must be configured to relay or copy the DHCP packets to the ISE PSNs, and the ISE PSNs must be configured to receive the DHCP packets on a specific interface.
References:
https://www.cisco.com/c/en/us/td/docs/security/ise/2-4/admin_guide/b_ISE_admin_guide_24/m_assetvisibility_
https://www.cisco.com/c/en/us/td/docs/security/ise/2-2/admin_guide/b_ise_admin_guide_22/b_ise_admin_guide