Point-to-Point Tunneling Protocol (PPTP)

The point-to-point tunneling protocol is an outdated method of establishing a VPN connection and constructing an encrypted tunnel. While this form of networking protocol was extremely popular in the early 2000s, modern innovations like OpenVPN and SASE offer a more secure remote connection solution.

The History and Evolution of PPTP

The point-to-point tunneling protocol was created in 1999 from a collaboration between several tech companies, the largest of which was Microsoft. For much of the early 2000s, this protocol was the industry standard due to its lightweight nature and how easy it was to set up.

However, over the last two decades, several PPTP vulnerabilities have been discovered in the core functionality of the protocol – leading it to be less frequently used than newer protocols.

The main vulnerabilities with this protocol lie within the PPP authentication protocol itself, with the Microsoft point-to-point encryption protocol having several major vulnerabilities that malicious actors can exploit.

There are major exploits related to MS-CHAP-v1, MS-CHAP-v2, and MPPE as a whole.

These vulnerabilities have been overcome in more recent VPN iterations, with the latest and most secure being SASE remote connection solutions. While not the same as a VPN, SASE solutions combine several technologies into one while delivering a similar technique.

How PPTP Works

The point-to-point tunneling protocol creates an encrypted tunnel between two points.

IP-wrapped data packets can pass through this tunnel, moving from one end to the other and being decrypted upon arrival. This form of connection works just like other VPN connections, allowing the receiving party to access sites on the internet with an additional layer of security.

There are three general steps that PPTP follows:

1. Connection Initiation: A user connects to their VPN, establishing a connection to its relevant port. This action creates a secure tunnel between two endpoints, using Microsoft’s PPTP encryption standard to maintain privacy within the tunnel.
2. Data Transformation and Encryption: The protocol transforms data into Generic Routing Encapsulation (GRE) packets and then encrypts them with the Microsoft point-to-point encryption algorithm.
3. Data Transmission and Reception: After encryption, data can now freely flow through the tunnel. This tunnel allows the endpoints to communicate with one another and the user to securely receive the data they want.

What is PPTP Passthrough?

PPTP utilizes GRE when transferring data, which some modern routers reject due to it being a less secure form of data transmission – some routers require you to enable a PPTP passthrough before using this form of VPN.

A PPTP passthrough is a rule on your router that allows it to support outdated PPTP connections.

Once enabled, your router will be able to host PPTP connections, allowing devices to receive data through this form of VPN.

Pros of PPTP

While PPTP is now obsolete and not widely used, there are still a few advantages of this form of VPN that made it especially useful in the 2000s:

• Speed of Transmission: PPTP uses a weaker encryption standard than those that modern VPNs use. While this is a negative for security, it does result in a faster transmission of data.
• Ease of Set up: Due to its lightweight nature, PPTP is compatible with numerous operating systems, which makes it extremely easy and reliable to set up.
• Compatibility: As PPTP was one of the main network transmission protocols, it is widely compatible with older machines. For those working on much older computers, you’ll often find that PPTP is compatible with your device. Modern devices may require a PPTP passthrough before working with this protocol.

Cons of PPTP

PPTP is now obsolete, with this being directly traced back to a series of disadvantages that the legacy technology contained:

• Weak Encryption: PPTP uses Microsoft’s early form of encryption, which is now long outdated due to its lack of efficacy.
• Limited Access: While older machines will accept PPTP, many modern networks and routers will reject this. Especially in business environments, you are very unlikely to find a network that will accept this protocol due to its lax security standards and known vulnerabilities.
• Reduced Features: As PPTP was an early pioneer in the industry, it has fewer features than modern network standards.
• Major Vulnerabilities: The most important disadvantage is that PPTP has several major known vulnerabilities that make it a target for hackers. Multiple cyberattack strategies, like man-in-the-middle attacks, function against PPTP, making it an unreliable form of encryption.

PPTP vs. Other VPN Protocols

The point-to-point tunneling protocol has been supplanted by a number of other VPN protocols that are all considered safer, more reliable, and more robust.

Here are some of the leading protocols:

• IKE and IPsec: Internet Key Exchange is a leading VPN management protocol that creates highly encrypted VPN tunnels. IPsec is the protocol that supports IP communications across these tunnels, helping to authenticate private connections.
• WireGuard Protocol: WireGuard protocol is a fast, lightweight, and secure VPN protocol. As a low-code VPN architecture, it is easy to set up and work with.
• L2TP and IPsec: Layer 2 Tunneling Protocol is a more modern protocol that works with IPsec to deliver highly secure VPN connections. L2TP creates the tunnel between endpoints, and IPsec then helps to encrypt and send data across.

VPN security with Check Point VPN

Although PPTP is now outdated, it laid the foundations for VPNs and network protocols that came after it. Businesses and individuals looking for more rigorous and secure VPN protocols should look at other, more modern network protocols.