Network Hardware Hardening 🌐🛠️

In this section, we'll cover various techniques to harden network hardware, making it more resilient against attacks. These methods are crucial for IT support specialists aiming to protect networks from unauthorized access and network-based attacks.

1. Rogue DHCP Server Attack Protection

• DHCP: A protocol that assigns network configuration information like IP addresses to devices on a network. It is a critical service and thus, a target for attackers.

• Rogue DHCP Attack: Attackers deploy unauthorized DHCP servers to distribute malicious configuration settings, such as fake gateways or DNS servers, to control traffic.

• DHCP Snooping: A feature in enterprise switches that monitors and tracks DHCP traffic. It builds a map of assigned IP addresses to physical switch ports, protecting against rogue DHCP servers, IP spoofing, and ARP poisoning.

2. ARP Spoofing and Dynamic ARP Inspection (DAI)

• ARP Spoofing: Attackers can forge ARP responses to redirect network traffic intended for another device, potentially enabling them to monitor or manipulate data.

• Dynamic ARP Inspection (DAI): Enterprise switches can prevent ARP spoofing by using information from DHCP snooping. DAI detects forged ARP packets (e.g., gratuitous ARP responses) and blocks them. Additionally, it can rate-limit ARP packets to prevent ARP scanning attempts.

3. IP Spoofing Prevention with IP Source Guard (IPSG)

• IP Spoofing: Attackers can send packets from a fake IP address to mislead network devices.

• IP Source Guard (IPSG): Using the DHCP snooping table, IPSG creates dynamic Access Control Lists (ACLs) for each switch port, dropping packets that do not match the assigned IP address.

4. 802.1X and EAP-TLS Authentication

• 802.1X: A standard for encapsulating Extensible Authentication Protocol (EAP) over 802 networks, also known as EAP over LAN (EAPoL).

  • Three Parties Involved:

    • Supplicant: The client device attempting to authenticate.

    • Authenticator: A switch or access point acting as a gatekeeper for network access.

    • Authentication Server: Typically a RADIUS server, responsible for verifying credentials.

• EAP-TLS: A secure EAP authentication type using TLS (Transport Layer Security) for mutual authentication between the client and server. It often requires client certificates for authentication.

  • Client-Side Certificates: Certificates provide additional security, especially when bound to client platforms using TPMs (Trusted Platform Modules), preventing theft and misuse.

5. TLS and HTTPS Connection Security

• TLS and PKI: The use of TLS in EAP-TLS relies on Public Key Infrastructure (PKI) for securing communications. This ensures the proper management of certificates and keys, both for clients and servers.

• Certificate-Based Authentication: EAP-TLS implementations commonly require a valid client certificate signed by the Certification Authority (CA), or a combination of certificates with credentials such as usernames, passwords, or even one-time passwords (OTP).

6. Securing Against Theft with TPMs and Full Disk Encryption (FDE)

• TPMs: Binding client-side certificates to devices using Trusted Platform Modules adds another layer of protection. This prevents unauthorized access to the network, even if the device is stolen.

• Full Disk Encryption (FDE): Combining TPMs with FDE ensures that even physical theft of a device does not compromise the network.

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By implementing these hardware hardening techniques, IT support specialists can effectively protect networks against a wide range of attacks, ensuring the security and integrity of the network infrastructure.

🌟 Key Concepts: DHCP Snooping, DAI, IPSG, 802.1X, EAP-TLS, TLS, TPMs, FDE