Why is IKEv1 deprecated?
Systems that support IKEv1 but not
The researchers found that IKEv1 is vulnerable to Bleichenbacher oracle attacks, a cryptographic attack technique that has been known for almost two decades. A Bleichenbacher attack involves sending modified ciphertext to a device and obtaining information about its unencrypted value based on the device's response.
IKEv2 is better than IKEv1. IKEv2 supports more features and is faster and more secure than IKEv1. IKEv2 uses leading encryption algorithms and high-end ciphers such as AES and ChaCha20, making it more secure than IKEv1. Its support for NAT-T and MOBIKE also makes it faster and more reliable than its predecessor.
In computing, Internet Key Exchange (IKE, sometimes IKEv1 or IKEv2, depending on version) is the protocol used to set up a security association (SA) in the IPsec protocol suite. IKE builds upon the Oakley protocol and ISAKMP.
Deprecating IKEv1
IKEv1 is deprecated and MUST NOT be deployed. Systems running IKEv1 should be upgraded and reconfigured to run IKEv2. Systems that support IKEv1 but not IKEv2 are most likely also unsuitable candidates for continued operation.
Internet Key Exchange (also known as IKE, IKEv1 or IKEv2) is a protocol that is used to generate a security association within the Internet Protocol Security protocol suite.
L2TP doesn't actually specify any mandatory encryption, but relies on PPP's MPPE encryption method. This is why it is almost always paired with IPSec, which supports up to AES-256. A big issue with IPSec is that it uses UDP port 500 and this makes it pretty easy to block by firewalls.
IKEv2 is one of the most reliable and secure protocols. It uses AES 256-bit encryption and supports various ciphers such as Camellia, 3DES, and ChaCha20. In addition, the protocol has perfect forward secrecy, and the MOBIKE feature will ensure your connection doesn't drop when shifting networks.
By encrypting your data and using private DNS servers, VPNs remain one of the most effective means of maintaining online privacy. Nevertheless, it's important to note that anything can be hacked.
IKEv2 provides the following benefits over IKEv1:
IKEv2 uses four messages; IKEv1 uses either nine messages (in main mode) or six messages (in aggressive mode). Built-in NAT-T (NAT Traversal) functionality improves compatibility between vendors.
Is IKEv2 more stable?
IKEv2 vs.
IKEv2 is more stable and can't be as easily blocked by a NAT firewall as L2TP.
About IKEv1 and IKEv2 for Azure VPN connections
In order to enhance the experience of customers using IKEv1 protocols, we are now allowing IKEv1 connections for all of the VPN gateway SKUs, except Basic SKU.
IKEv1 phase 1 negotiation aims to establish the IKE SA. This process supports the main mode and aggressive mode. Main mode uses six ISAKMP messages to establish the IKE SA, but aggressive mode uses only three. Therefore, aggressive mode is faster in IKE SA establishment.
While Aggressive Mode is faster than Main Mode, it is less secure because it reveals the unencrypted authentication hash (the PSK). Aggressive Mode is used more often because Main Mode has the added complexity of requiring clients connecting to the VPN to have static IP addresses or to have certificates installed.
IKEv1 Phase 1 negotiation can happen in two modes, either using Main Mode or using Aggressive Mode. IKEv1 Phase 1 Main mode has three pairs of messages (total six messages) between IPSec peers. IKE Phase 1 Aggressive Mode has only three message exchanges. The purpose of IKEv1 Phase 1 is to establish IKE SA.
The only reason why you should be running ikev1 should be if you are using an old device which does not support ikev2. If you implement your VPNs in a correct and way with strong crypto, it's very likely that your VPNs are the strongest element of your complete security-chain.
Internet Key Exchange (IKE) is the protocol used to set up a secure, authenticated communications channel between two parties. IKE typically uses X. 509 PKI certificates for authentication and the Diffie–Hellman key exchange protocol to set up a shared session secret.
The Internet Security Association and Key Management Protocol (ISAKMP) defines the procedures for authenticating a communicating peer, creation and management of Security Associations, key generation techniques, and threat mitigation (e.g. denial of service and replay attacks).
Interaction Between IKE and IPSec
Internet Key Exchange (IKE) protocol— IPsec supports automated generation and negotiation of keys and security associations using the IKE protocol. Using IKE to negotiate VPNs between two endpoints provides more security than the manual key exchange.
Performance: In many cases IKEv2 is faster than OpenVPN since it is less CPU-intensive. There are, however, numerous variables that affect speed, so this may not apply in all use cases. From a performance standpoint with mobile users, IKEv2 may be the best option because it does well establishing a reconnection.
Does L2TP encrypt data?
On its own, L2TP does not provide any encryption or confidentiality to traffic that passes through it, so it is usually implemented with the IPsec authentication suite (L2TP/IPsec).
Better Security
Since L2TP doesn't have any encryption or authentication capabilities (both are key features of VPNs) on its own, IPSec VPN is often paired with it.
The L2TP protocol can be highly secure when used in conjunction with IPSec. It is highly compatible, working on operating systems like Windows and macOS by default. L2TP (and L2TP/IPSec) are relatively easy to set up due to their high compatibility. More firewall-friendly as it runs over UDP protocol.
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OpenVPN vs L2TP.
| OpenVPN | L2TP/IPsec | |
|---|---|---|
| Stability | Most reliable and stable, even behind wireless routers, on non-reliable networks, and on Wi-Fi hotspots | Stable on NAT-supported devices |
Many VPN experts recommend OpenVPN as the most secure protocol. It uses 256-bit encryption as a default but also offers other ciphers such as 3DES (triple data encryption standard), Blowfish, CAST-128, and AES (Advanced Encryption Standard).
Firewall ports
IKEv2 is easier to block than OpenVPN due to its reliance on fixed protocols and ports. OpenVPN can be easily configured to run on any port using either UDP or TCP thereby easily bypassing restrictive firewalls. WireGuard® uses the UDP protocol and can be configured to use any port.
Wireguard has better performance/throughput and uses less bandwidth than OpenVPN. IKEv2 is probably more secure (256-bit encryption through IPSec)...
Within the term "IPsec," "IP" stands for "Internet Protocol" and "sec" for "secure." The Internet Protocol is the main routing protocol used on the Internet; it designates where data will go using IP addresses. IPsec is secure because it adds encryption* and authentication to this process.
The IPsec protocol suite operates at the network layer of the OSI model. It runs directly on top of IP (the Internet Protocol), which is responsible for routing data packets. Meanwhile, SSL operates at the application layer of the OSI model. It encrypts HTTP traffic instead of directly encrypting IP packets.
Researchers have demonstrated that the Internet protocol 'IPsec' is vulnerable to attacks. The Internet Key Exchange protocol 'IKEv1', which is part of the protocol family, has vulnerabilities that enable potential attackers to interfere with the communication process and intercept specific information.
Does AWS support IKEv2?
We are excited to announce that AWS Site-to-Site VPN now supports Internet Key Exchange version 2 (IKEv2) for tunnel setup. Starting today, new VPN connections will be able to use IKEv2 or IKEv1 to negotiate a VPN session.
IKEv2 Phases
Like IKEv1, IKEv2 also has a two-phase negotiation process to create a secure tunnel. The first phase of IKEv2 is IKE_SA_INIT and the second phase of IKEv2 is IKE_AUTH.
About IKEv1 and IKEv2 for Azure VPN connections
In order to enhance the experience of customers using IKEv1 protocols, we are now allowing IKEv1 connections for all of the VPN gateway SKUs, except Basic SKU.
IKEv1 phase 1 negotiation aims to establish the IKE SA. This process supports the main mode and aggressive mode. Main mode uses six ISAKMP messages to establish the IKE SA, but aggressive mode uses only three. Therefore, aggressive mode is faster in IKE SA establishment.
For IKEv2, the SA that carries IKE messages is referred to as the IKE SA, and the SAs for ESP and AH are child SAs. For IKEv1, the corresponding terms for the two types of SAs are "ISAKMP SA" and "IPSec SA".
IKEv1 Phase 1 negotiation can happen in two modes, either using Main Mode or using Aggressive Mode. IKEv1 Phase 1 Main mode has three pairs of messages (total six messages) between IPSec peers. IKE Phase 1 Aggressive Mode has only three message exchanges. The purpose of IKEv1 Phase 1 is to establish IKE SA.
