Multiprotocol Label Switching (MPLS) networks are protected, meaning only selected devices and systems are allowed inside the network. An outside user cannot access the inside without authorization. This blocks unauthorized access by trusted insiders, or by hackers that gain access to network assets.
Enterprises can take steps to protect against attacks, such as:
- Limiting physical access privileges.
- Controlling network traffic with routers, firewalls, and intrusion detection devices.
- Restricting administrative privileges for non-essential users.
- Monitoring network activity for anomalous events using log files and IDS/IPS security tools.
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What is MPLS Security?
Multi-Protocol Label Switching (MPLS) security protects the MPLS network. It provides services like the quality of service (QoS), traffic engineering, and fast recovery mechanisms. To be secure, MPLS needs protection against Denial of Service attacks, distributed denial of service attacks, and other malicious hacks.
Benefits of MPLS Security
MPLS, often used in enterprise networks, can be set up to achieve extremely high levels of security and reliability. MPLS also offers greater flexibility and visibility by supporting more than one service type over a single label-switched path (LSP).
In particular, MPLS provides the following benefits:
- With MPLS VPNs, enterprises can securely extend their private IP address space across public IP networks without exposing it to outside threats.
- Virtual Private Networks (VPNs) protect data using encryption, which secures information as it traverses the public Internet or other open networks.
- Unlike some other types of encrypted traffic, MPLS does not slow down the speed at which data travels over a connection because it does not encrypt at each point along the way.
- The hardware-based switching capabilities of MPLS provide faster performance than software-based switches, making them ideal for environments where latency is critical such as VoIP, real-time streaming video applications, and wireless networks.
It’s important to understand why there’s so much hype around MPLS. At its core, MPLS relies upon advanced technology mechanisms—some of which go beyond simple labeling schemes—that enable users to gain security and scalability benefits right out of the box.
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MPLS offers several features that ensure safety
As noted earlier, virtual private networks (VPNs) allow companies to route data packets securely over the public internet by employing various techniques, such as encryption. For example, the IPsec standard enables user devices to communicate with each other through secure tunnels.
This way, all data transmissions are encrypted and cannot be read by outsiders unless they possess decryption keys. When using MPLS, these same principles apply but with one key difference. Instead of relying solely on keys to secure connections between two points, the label switched path mechanism also makes use of labels.
These labels can be applied by routers at either end of a given connection and then switched accordingly within the network. Once received, the router uses decapsulation to strip away the outer packet before forwarding it to its final destination. This approach ensures that even if someone managed to hack into a router somewhere along the network path and intercept the packet, they still wouldn’t be able to read what was inside due to this process.
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Top 10 MPLS Security Best Practices
Implementing these best practices can help maintain a secure and reliable data flow over MPLS networks and protect them from risks such as IP address spoofing attacks, access control list violations, and denial of service attacks.
1) Separate Control Plane and Data Plane
The control plane provides information that the data plane needs to forward data from one network node to another. It is used for routing decisions, monitoring network-related statistics, and setting up protocols like Routing Information Protocols (RIP). The two planes are typically separated for added security.
With this separation, if a malicious actor takes over a device on the control plane, it will not be able to modify or intercept traffic on the data plane. You can create separate networks with firewalls between them or employ routing protocols like OSPF or BGP, which have authentication mechanisms in place to limit access to each protocol level.
2) Employ a Defense-in-Depth Strategy
Defense-in-depth employs multiple layers of security measures or defensive strategies. This would entail deploying packet filtering, firewalls, and intrusion detection systems in a layered fashion in MPLS networks. For example, patrol the network perimeter with an IDS system.
To further protect internal resources, use an inline IPS for deep inspection of traffic entering the intranet, and implement application-level gateway devices for review and protection. In addition, implement a firewall policy that blocks access to all unnecessary ports at the perimeter and only allows established connections through specific ports where needed.
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3) Use ACL to allow only necessary hosts/routers into the MPLS domain
When the MPLS network is set up, it should be made as secure as possible by placing access control lists (ACLs) at the edge of the MPLS domain that allow only trusted devices access to the MPLS domain.
These ACLs are used with ping and traceroute commands, which can be run periodically against hosts inside and outside the MPLS domain to determine if traffic flows properly through all points on a given network.
4) Deploy firewalls at all nodes to filter out unauthorized packets
Firewalls can control where and what traffic is allowed in or out of the MPLS network. Inbound firewalls protect the MPLS network from malicious software (e.g., viruses, malware) on an incoming computer. In contrast, outbound firewalls help guard against hacker attacks by filtering out unauthorized packets from exiting the MPLS network.
To reduce vulnerability to a denial-of-service attack, deploy multiple firewalls at all nodes. Use these best practices:
- Packet filtering: Packet filtering allows a firewall administrator to configure which type of packet should be blocked or forwarded.
- Authentication: This option requires users who want access to the MPLS network to provide means of identification before being granted access through a firewall.
- Captive portals: These gateways require users to connect to the MPLS network to authenticate themselves with a username and password.
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5) Use ingress and egress filtering
Establish security zones on every ingress/egress point: Establish security zones on every ingress/egress point to maintain separation between networks and set rules accordingly.
With ingress filtering in place, the connection will be allowed if it originates from a trusted network; in the case of egress filtering, the connection will be allowed if it is destined for a trusted network.
In both cases, the firewall will drop an attempt to reach a source or destination host on an untrusted network. Filtering out all packets with invalid headers, such as packets that do not conform to IP protocol standards, can also prevent attacks. Allowing access to certain protocols can also help keep the enterprise networks safe. Interfaces should be monitored continuously. Network admins should monitor the ingress and egress ports of routers connected to external links for unexpected spikes in traffic volume.
6) Implement bandwidth limits on each link with appropriate policing and shaping policies
Bandwidth limits are often one of the first tools used to control traffic on a network, but they are not always configured correctly. Incorrect bandwidth limiting is ineffective because it leaves gaps where congestion could occur and can lead to oversubscription. Therefore, bandwidth limits must be applied at each Layer 2 link with appropriate policing and shaping policies such as Token Bucket in MPLS QoS for the multiservice networks.
7) Enable encryption between PE and CE routers
One of the best ways to protect MPLS networks is by using an end-to-end VPN tunnel between the provider edge (PE) routers and customer edge (CE) routers. It is important to utilize the benefits of encryption when connecting the PE router to CE routers, especially when there are multiple router hops.
When a packet traverses from one router to another, there is a possibility for eavesdropping, data tampering, or message insertion attacks. To combat these attacks, you can use IPsec as a security measure. With IPsec enabled on both routers, it will encrypt and decrypt traffic between the two devices and offer an extra layer of protection against those aforementioned attacks.
8) Encrypt everything where possible
MPLS encryption is accomplished through a combination of Digital Encryption Standard (DES) and 3DES or Advanced Encryption Standard (AES) encryption. In addition, IPSec, Layer 2 Tunneling Protocol (L2TP), and Secure Socket Layer/Transport Layer Security (SSL/TLS) are common methods for encrypting VPN traffic over MPLS networks. All these protocols can be deployed independently or in conjunction with one another.
Some enterprises use combinations of the different protocols on their MPLS networks because they can interoperate with other security measures they have deployed elsewhere in their network infrastructure. MPLS VPNs may also provide data confidentiality using transport mode IPsec ESP encryption. Data integrity can be maintained using an ESP integrity algorithm such as HMAC-MD5, HMAC-SHA1, or HMAC-SHA256.
9) Implement a robust IDPS solution for enterprise MPLS network
The intrusion detection and prevention systems (IDPS) provide real-time protection against attacks. Attackers will try to overwhelm the network by sending packets that are not permitted. IDPS can handle these packets by being programmed for specific levels of load or attack types. The IDPS analyzes all packets entering and exiting the enterprise network and blocks those deemed malicious.
10) Deploy anomaly-based detection
Enterprise MPLS network security is achieved through a proactive rather than reactive approach. Anomaly-based detection detects abnormal activity in traffic patterns on the MPLS backbone. It monitors every packet flow on the network, thus providing full coverage and a low false positive rate.
Anomaly-based detection also aids in identifying stealthy attacks, such as new ones created by hackers, who find vulnerabilities and exploit them without triggering any alarms. Identify stealthy attacks by analyzing changes in behavior over time using statistical data. Using anomaly-based detection, enterprises can pinpoint the exact point when attackers entered their network, and take appropriate measures immediately.
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