- Mauritania was taken offline for two days late last month after a submarine internet cable was cut.
- No one knows why or how it was cut, though Sierra Leone’s government appears to have interfered with its citizens’ internet access around that time.
- Undersea web cables are uniquely vulnerable to sabotage.
- UK and US military officials have previously indicated that Russia is capable of trying something like this, though there is no indication that it was involved in this break.
LONDON – For years, countries have worried that a hostile foreign power might cut the undersea cables that supply the world with internet service.
Late last month, we got a taste of what that might be like. An entire country, Mauritania, was taken offline for two days because an undersea cable was cut.
The 17,000-kilometer African Coast to Europe submarine cable, which connects 22 countries from France to South Africa, was severed on March 30, cutting off web access partially or totally to the residents of Sierra Leone and Mauritania.
It also affected service in Ivory Coast, Senegal, Equatorial Guinea, Guinea, Guinea Bissau, Liberia, Gambia, and Benin, according to Dyn, a web-infrastructure company owned by Oracle.
There had not been a significant outage along the cable in the past five years.
Loss of service to Mauritania was particularly severe, as the Dyn chart below shows.
“The most significant and longest-lasting disruption was seen in Mauritania, with a complete outage lasting for nearly 48 hours, followed by partial restoration of connectivity,” David Belson wrote in a Dyn research blog on Thursday.
The international cable system has several levels of built-in redundancy that allowed providers such as Africell, Orange, Sierra Leone Cable, and Sierratel to restore service.
But the break shows just how vulnerable the worldwide web is to the simple act of cutting a cable. About 97% of all international data is carried on such cables, according to the Asia-Pacific Economic Cooperation forum.
Here’s a map from the telecom analytics company TeleGeography of the cables in Europe:
And those connecting the US:
In 2013, three divers were arrested in Egypt after attempting to cut submarine web cables.
“In the most severe scenario of an all-out attack upon undersea cable infrastructure by a hostile actor the impact of connectivity loss is potentially catastrophic, but even relatively limited sabotage has the potential to cause significant economic disruption and damage military communications,” James Stavridis, a retired US Navy admiral, said in a 2017 report for the think tank Policy Exchange.
“Russian submarine forces have undertaken detailed monitoring and targeting activities in the vicinity of North Atlantic deep-sea cable infrastructure,” he added.
There is no indication that Russia was involved in the ACE breakage. But military strategists are likely to study the Mauritania break as an example of the effect of knocking a country off the web by cutting its cables.
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