Network Tunnel Vulnerabilities

Network tunneling is a process that involves encapsulating network packets into another packet. This can be done for several reasons, but the most common are security and performance. Network tunnels are used to securely connect networks without having to go through potentially insecure paths or do unnecessary processing on data. However, there are some vulnerabilities in this practice that you should know about before using it yourself.

What is Network Tunneling?

A network tunnel is a means of connecting two networks that are not on the same system while sending data between them. This can be done by encapsulating packets in another packet, or providing logical links to remote systems through an encrypted connection over untrusted networks. This is done to provide security or performance benefits.

Vulnerabilities in Network Tunnels

Network tunneling can be vulnerable if not implemented with proper care. There are several types of vulnerabilities that you should know about before implementing your own system for this purpose, including:

Tunnel-related DoS attacks – where the traffic being routed through a connection becomes so heavy that it reduces the throughput of other connections on the same router
Tunnel spoofing – packets with false source addresses might be sent over an encrypted link using IPsec, which will create problems at intermediate routers and cause data loss during transit
Traffic sniffers – some highly advanced attackers may try to use special tools like ARP cache poisoning to get hold of passwords used for authentication purposes (e.g., EAP-MD)
Tunnel-specific attacks – if the tunnel allows attackers to send packets with spoofed source addresses, this can create problems for any destination address on either side of the connection
Man in the middle (MITM) attacks – where an attacker inserts themselves into a conversation between two endpoints without telling each endpoint about it. This enables them to gather information that they wouldn’t be able to get otherwise or even change what is being sent back and forth
IPsec policy manipulation – some sophisticated hackers might try changing policies in order to break authentication keys used by IPsec communications. If successful, they could decrypt every packet passing through your network until you find out how it happened and fix it.

Other types of attack may also involve tunneling, such as:

Coss-site tunneling (XST) which is used to carry out data theft or other unauthorized activities. It is also used to hide malicious traffic, which makes it harder for network administrators to detect. XST can be done by encoding data into the pixels of an image file or other seemingly harmless method that would not seem out of place within regular browsing activity
SSL tunneling – this type of attack uses a so-called “man in the browser” approach where all messages are sent via SSL/TLS channels without being decrypted along the way. This enables attackers to send all kinds of requests through your system including uploading files and executing commands on remote systems just like they were sitting at your computer’s keyboard doing it themselves
Unauthorized VPN access – sometimes employees may try accessing corporate networks using unauthorized means as VPNs without creating their own tunnels. This can create problems for network administrators when every connection is treated as equal and it becomes hard to tell who should be allowed access to what.
Unauthorized tunnels – attackers can also create their own encrypted connections between different networks without proper authorization, which could compromise the security of your system and the information it contains.

How to Prevent Tunnel-related Problems?

There are several ways that you can protect yourself from network tunnel vulnerabilities, including:

Filtering packets at the edge – this is a good way of blocking unwanted traffic before it even gets into your system. You should make sure all incoming connections are authorized and use strong forms of authentication like EAP or two factor for added security
Using end-point tracking – enable logging on both ends of VPNs so that you know who has been accessing them, which hosts they have connected to and when these events occurred (e.g., using iptables logs). This information may prove invaluable during forensic investigations if malicious activity ever does occur on your systems
Creating policies with care – you should also be careful about how your policies are configured, since these will have an effect on whether traffic is allowed to pass through or not. For example, restricting outbound access while allowing inbound connections may cause problems for legitimate users who need to do anything outside of your network
Enforcing IPsec authentication – you can also configure strong forms of IPsec authentication that uses digital certificates and private keys rather than user names/passwords which could fall into the wrong hands more easily
Using anti-tunneling tools – there are several different types of software available including countermeasures against XST attacks (e.g., firewalls), man-in-the middle attack prevention (e.g., SSL interception) and detection systems against tunneled threats (e.g., IPS/IDS).

Frequently Asked Questions:

Q. Is end point tracking effective in preventing unauthorized VPN tunnels?

A. Yes – enabling logging on both ends of the tunnels has proved useful in investigations where malicious activity occurs on your systems or networks

Q. What is anti-tunneling software used for exactly?

A. This type of security tool is designed to detect suspicious traffic patterns like XSTs, man in the middle attacks as well as protect against policy tampering which could be a sign an attack may be underway.

Q. Is SSL interception used in tunnel vulnerability prevention?

A. Yes – this type of countermeasure can be put into place to allow for decryption and inspection of transmitted data, which is necessary when you need to determine the source and destination information within packets.