Data protection is a multidisciplinary activity and needs to be prepared for any possible type of attack – cyber and physical. Most threats are online, but one must not underestimate the risks inherent in stolen laptops or hard disks.

One of the oldest and still most frequent approaches is to intercept the data passing over a link to extract valuable information. Eavesdropping on a copper cable is simple and usually does not affect original transmissions, making it almost impossible to detect. Transmissions over fibre were considered to be intrinsically secure, but eavesdropping from a link is still possible.

Prevent eavesdropping

The reason why fibre can be hacked resides in the excess of optical power used on the link. This makes it possible to extract part of the power, without affecting the receiving side and generating any alarm.

Once a fibre network has been designed, a high optical margin is always considered, in order to avoid problems caused by dust on the connectors or transmitter, receiver optic degradation or signal loss due to fibre bending. This optical power can be diverted to duplicate the original data. This approach affects the transmission, and like a very low signal loss it goes undetected.

Usually, this is done by bending the fibre and intercepting the light passing through the fibre shield with an optical sensor.

Fibre-optic links are used extensively for long-range data communications and are also a popular choice for local area networks. Because this kind of transmission is often assumed to be secure, the level of scrutiny on it can decrease, leaving the door open to potential hacking.

To avoid this problem, the legacy approach requires that dedicated hardware is added on the transmission and receiving side to monitor the optical link power, which generates alarms once an unexpected variation occurs. This kind of variation means that the fibre has been bent somewhere and a potential attack is occurring.

This approach requires a costly initial investment as well as ongoing maintenance, which is where Allied Telesis comes in.

A unique system

The company’s active fibre monitoring (AFM) technology adds an important piece to the security puzzle by constantly monitoring the amount of light received on a fibre link, and detecting any deviations. When an intrusion is attempted, the light level changes, because some of it is redirected by the eavesdropper onto another fibre. As soon as this happens, AFM detects the intrusion and raises the alarm. The link can either be shut down automatically or an operator can be alerted and manually intervene.

Configuration is simple – just set and forget. Monitoring is non-stop, and any tampering or intrusion on an optical link is quickly detected. AFM is sensitive and smart, so false alarms are not a problem.

AFM is a built-in feature on all network switches and firewall products running Allied Telesis’ latest AlliedWare Plus operating system, in conjunction with the company’s digital diagnostic monitoring-capable small form-factor pluggable (SFP) and SFP+ optical modules.

Allied Telesis’ dedicated team constantly address network security concerns and focus on maintaining the latest security features within the AlliedWare Plus operating system.

AFM provides specialised data protection. Users can enjoy non-stop, automated monitoring of all their optical fibre with no need for expensive third-party equipment. With this in mind, it is the perfect security system for fibre networks in defence and security, where outside hacking is becoming increasingly widespread.