Examkin

Question

Difficulty: HardVirtual Private Networks and Remote Access Security

A network security administrator is auditing packet captures of an IKEv2 remote access VPN connection. Place the stages of the IPsec IKEv2 session setup in the correct chronological order from initial connection attempt to payload data transmission.

  1. 1Negotiate cryptographic proposals and exchange Diffie-Hellman public values and nonces in unencrypted plaintext (IKE_SA_INIT).
  2. 2Calculate the shared secret to derive keying material and enable encryption and integrity protection for the control channel.
  3. 3Exchange authenticated peer identities and verification credentials within the encrypted control channel (IKE_AUTH).
  4. 4Establish the Child Security Association (IPsec SA) parameters and traffic selectors for protecting user data packets.

Answer

The correct order begins with negotiating cryptographic parameters and exchanging Diffie-Hellman values in cleartext (IKE_SA_INIT), followed by deriving keying material from the shared secret to encrypt the control channel, then exchanging authenticated identities securely (IKE_AUTH), and concluding with establishing the Child Security Association (IPsec SA) for user data traffic.
IKEv2 session establishment follows a strict sequence: first, the IKE_SA_INIT exchange establishes cryptographic algorithms and shares Diffie-Hellman keys in cleartext. Second, both sides calculate the shared secret to encrypt the control channel. Third, the IKE_AUTH exchange transmits encrypted identity and credential information. Finally, Child SAs are negotiated to encrypt actual user data traffic.

Step-by-Step Solution

1
Identify the initial unencrypted parameters exchange stage
The endpoints execute the IKE_SA_INIT exchange to agree on algorithms and share public Diffie-Hellman values.
Cryptographic material must be exchanged first so that a secure channel can be derived before sensitive identities are shared.
2
Determine control plane key derivation
Both peers compute the Diffie-Hellman shared secret and generate symmetric encryption keys.
Symmetric key derivation is required to activate encryption and integrity checks on all subsequent control messages.
3
Identify peer identity authentication stage
The endpoints send encrypted authentication payloads during the IKE_AUTH phase.
Authenticating within the encrypted channel prevents eavesdroppers from harvesting username/certificate identity information.
4
Identify user payload tunnel establishment stage
The peers finalize Child SA creation and define traffic selectors for ESP encapsulation.
Child SAs define the specific security parameters used to protect end-user application data passing through the tunnel.

Key Concept

IKEv2 IPsec VPN Tunnel Negotiation Sequence
Rate this question

Topics

Virtual Private Networks and Remote Access Security

More questions from this topic