Russia Is Trying to Tap Transatlantic Cables

The Times of London is reporting that Russian agents are in Ireland probing transatlantic communications cables.

Ireland is the landing point for undersea cables which carry internet traffic between America, Britain and Europe. The cables enable millions of people to communicate and allow financial transactions to take place seamlessly.

Garda and military sources believe the agents were sent by the GRU, the military intelligence branch of the Russian armed forces which was blamed for the nerve agent attack in Britain on Sergei Skripal, a former Russian intelligence officer.

This is nothing new. The NSA and GCHQ have been doing this for decades.

Boing Boing post.

Posted on February 24, 2020 at 6:27 AM31 Comments


thatguy February 24, 2020 6:57 AM

I’ve got a bit of a question to any of the more experienced tech people than myself. When it comes to the business of tapping a 1500 mile+ fiber optic cable under the ocean, when your nation of choice choses a perceieved fruitful spot in the line to “tap”. Do you splice in your own fiber at that point, and then run another line from that spot back to you home country? Wouldnt this be noticeable? Or do they install some device at the splice point capable of transmitting incredible amounts of wireless data to a receiver somewhere? Obviously, a device like this would be battery operated and temporary. Asking for a friend…

AndyM February 24, 2020 8:24 AM

Unlikely they are trying to ‘tap’ the cables, more likely they want to know exactly where they are so that they can quickly sever them if needed.

There have been multiple cases of fibres being deliberately cut in California, Europe and the Middle East. These cables are of strategic importance to many countries, cutting them at just the right time could be very damaging.

POLAR February 24, 2020 9:10 AM

That akward moment when the deer is accusing the moose of having horns.

@thatguy Obviously you can tap submarine, international TB/s lines without anyone noticing, but only if you wear dark shades and a grey coat.
But the real deal is subverting american preferences with psychic facebook cats and squirrels towards some democrat president like Obama, to raise the inter-superpowers tension so high they can have a proper termonuclear war. Oh, you selfish commies. Luckily, the agents didn’t respond properly to the “Feck banjaxed the cable” yelled at them, and the evil plan got spoiled.

Clive Robinson February 24, 2020 9:17 AM

@ thatguy,

When it comes to the business of tapping a 1500 mile+ fiber optic cable under the ocean

You don’t if you can avoid it.

Any attempt to tap a fiber optic cable changes it’s characteristics. As they operate these fibers as near maximum as they can such changes will show up in the reduced performance.

If they are going for the underwater option they would most likely do it at a signal repeater which is used to amplify the signal etc. Tapping this can be done with minimal changes to the circuits characteristics.

But they probably would do it on land between the beach head and the multiplexor center, it’s what the likes of the NSA, GCHQ and similar do, and have done since before fiber optic cables got their toes wet as it were.

What happens is the subsea cable gets “trenched in” from a mile or so off shore up ubder the beach to a building that is often unmaned. In this building the fiber optic cables are terminated and in quite a few cases de-multiplexed and sent off to different “carriers” via fairly standard “high capacity telco grade back hauls”. These then rise in the carriers regional network node (look up bude in cornwall UK) where the traffic might go down another subsea cable, up ibto a satellite or into a national network”.

The point is in the case of the UK and Cornwall many of the cables that come up there traffic is not destined for the UK it’s destined for Africa, Europe, Middle East and Asia, with some going to Australia and New Zeland.

Strange as this might sound it came about due to the Victorians. Once you put in the fascilities for one cable, each successive cable costs less to bring there and the likes of traffic switching becomes easier. So with time many cables end up at just a handfull of choke points with by far the majority in British or British Colonial lands. Which is one of the big things GCHQ bring to the Five-Eyes table. What the US has in more recent times tried to do is make all Internet traffic flow through the US in one way or another. Even if they don’t get the data, they can get meta-data via the DNS and similar backend or hidden infrastructure systems.

Along with the Five-Eyes activities, China is known to have specialised submarines to do all sorts of interesting things, thus the choke points at Australia and the South China Seas probably have several nations that have gained access on way or another.

If you have a quick search on line you can find a world map with a lot of the subsea cables on it. Because for various reasons any subsea cable laying fairly quickly gets into the public domain one way or another including those that are supposedly secret.

POLAR February 24, 2020 9:18 AM

@thatguy Obviously I was being sarcastic, not at you but at the uneducated press saying all kinds of nonsense. Whether it could be done by penetrating the cable or not(Tempest-like attack, maybe at signal repeaters points where there’s a bit of EMI instead of just light passing through the fibers..?), well nobody is gonna tell ya, so hell, whatever. Have a nice day 🙂

thatguy February 24, 2020 10:39 AM

@ Clive Robinson

Thanks for the very detailed response. Very nifty technological tricks that are being utilized. Its fun to read about this sort of thing.


No worries 😀 I thought your response was rather enjoyable. I didnt figure I would get an honest answer, but it was worth a shot. Im sure Clives post wasnt too far off!

Etienne February 24, 2020 1:17 PM

This blog article uses “tap” while the referenced article uses “crack”.

crack (verb) – To break down or yield
tap (noun) – A connection made to an electrical conductor without breaking it

One being brute, the other finesse.

Whatever the case, it shows the importance of using long keys in symmetric cryptography, as these cables are bound to repeat keys at phenomenal rates given the traffic density.

Petre Peter February 24, 2020 3:59 PM

Companies like Apple might put up their own satellite so that they can bypass the telecos and the phone would work out of the box. Tyrants and dictators beware.

Jonathan Wilson February 24, 2020 4:28 PM

If you are sending any kind of sensitive data that goes over something like an international fiber link you need to assume that someone could be listening and spying on it and send it encrypted.

Geoffrey Nicoletti February 24, 2020 4:36 PM

Could one do a “splitter” op? What device do you leave on the sea floor? Can it implant “misinformation” or worse? And whatever the op of GRU here—why is a success better than the capability the Russians already have? I have a lot of technical questions for this nation-state fiber hack…

vas pup February 24, 2020 4:59 PM

I’ll agree with point of @AndyM.
Recently it was discussed in detaile on this respected blog when special RF submarine named “Losharik” caught fire, and several high ranking naval officer were killed by fire on it.

don k February 24, 2020 5:35 PM

The more or less definitive essay on undersea cables was written by Neil Stephenson in 1996. It’s available at and is a really terrific read. I don’t recall that it has instructions for tapping into the data stream. But it might. Highly recommended.

Tatütata February 24, 2020 8:54 PM

I feel this article overstates the importance of Eire in the cable business, and most of its content is short on hard facts and long on speculation and fear mongering.

According to the Submarine Cable Map web site, there is only one direct transatlantic cable terminating entirely in Ireland, AEconnect-1, linking Long Island NY with Kilala in County Mayo. The few other cables from America are multi-drop systems with branch extensions touching Ireland. Almost all other cables cross the Irish sea and connect to various points from Cornwall to Scotland.

AEconnect’s operator, , touts their “North Atlantic Loop” as delivering “secure, resilient transatlantic connectivity”. Their system consists of two widely separated cables, and cross-connections at both ends.

Sabotage would have mostly nuisance value, unless it is massive and simulatneous. Such a situation would be just short of launching nukes.

From the sheer bandwidth of fiber optics, I think it beyond the means of an economically struggling Russia to create the necessary equipment to create practical undersea wiretaps. If they had the technical talent and industrial might, they would be better off offering terminals on the open market. Now, suppose they had a partner… (China?).

Drew February 25, 2020 12:13 AM

Not very successful GRU operation if London Times got to know about it.
Why would GRU even consider doing this operation – to gain access to some encrypted data which they might have means of decrypting (would be interesting) or to place some remote controlled explosives to detonate and sever the cables at the time of their choosing?
Is this the sort of speculating your after on this blog?

Clive Robinson February 25, 2020 3:31 AM

@ Drew,

Is this the sort of speculating your after on this blog?

Once a long time ago ICT security and Physical securiry were seen as seperate. ICT came effectively under the business side often “accounts” and physical security under facilities / Plant managment and neither talked to each other much.

Since then the criminals have forced there to be a little more dialog…

But when you consider major “Denial of Service” attacks the winner so far appears to be the most acrobatic of vandals the squirrel member of the rodent family.

The point being that security threats come from any and all directions, and looking only in one direction will mean that you will eventually get “sandbaged” from behind.

metaschima February 25, 2020 6:15 AM

I would have to agree with the idea that this is just reconisence for future disruption of transatlantic network communication, and not “tapping” the cable. It makes no sense to tap the cable, not only is it extremely difficult, but you won’t really gain anything valuable in return. These cables carry immense amounts of information, and any important information would likely be encrypted, and I don’t see why you wouldn’t be able to get the data in a much easier way. Such agencies have the capability of highly covert and targeted attacks in order to gain valuable information, and it only makes sense to do it this way, because it the best and most efficient way. People must have a very outdated notion of “tapping” as in tapping a phone line, no that’s a whole different animal to tapping a transatlantic fiberoptic cable.

Tatütata February 25, 2020 7:49 AM

Strange as this might sound it came about due to the Victorians. Once you put in the fascilities for one cable, each successive cable costs less to bring there and the likes of traffic switching becomes easier. So with time many cables end up at just a handfull of choke points with by far the majority in British or British Colonial lands.

Geography is one way to explain the British near-monopoly in telegraph cables, but then cables could have just as well been landed in Brittany.

Another explanation for that preeminence is a confluence of the financial power of London markets for raising capital (investments in cables were initially extremely risky), a far-flung empire, an industrial base, an access to raw material (in particular copper and gutta-percha), imperial power and needs, and scientific talent (it did take several attempts to get everything right). (Tell that to brexiters…) France had many of the same characteristics, but had perhaps less immediate interests in North-America.

The US resented this monopoly (justifiably so, in view of the Zimmermann telegram), especially during WW1 (the British navy cut off and stole direct German cables to neutral America in the very first minutes of the conflict in August 1914), and endeavoured to diversify her connections. For example, most of the capable cables to Central and South America (Uncle Sam’s private backyard, according to the infamous Monroe doctrine) were in British hands, which resisted or complicated any forwarding of traffic to and from US controlled systems.

The solution was to foster the development of wireless, and impose conditions on the landing of foreign cables on US territory.

The US wasn’t the only one concerned by the monopoly. Sweden had a perfectly good connection to the British cable system (and Room 40…), but after WW1 was convinced around 1920 to buy a rather costly Alexanderson transmitter from RCA to establish a direct link to America (radio station “SAQ” in Grimeton). A very similar station was built in Poland, which had newly become independent, and obviously couldn’t rely on her immediate neighbours to carry traffic.

Clive Robinson February 25, 2020 9:13 AM

@ Tatütata,

And there was me thinking I was the only regular commenter here with an interest in early communications systems.

Oh and as you note,

the financial power of London markets for raising capital (investments in cables were initially extremely risky)

Risky as it was, it is an investment that has paid off over and over not just financially but politically down the years.

But it also pushed technology forward, those transmitters you mention came about because of the transmission line work that came out of the cables.

Which by the way there is evidence that RCA amongst others in the US in effect stole by ignoring patents or published science (something ironically the US now accuses others of…).

QX1047 February 25, 2020 10:18 AM

How dare they tap them anyway. That they even. What are they thinking, to listen to our conversations or something? So crass. Our very own NSA would never do such a thing.

nottheone February 25, 2020 11:20 AM

I have worked with optic fibre cables before (a lot). It is actually possible to kind of “open the cable” and expose the actual fibers without actually cutting the cable (very difficult, however possible, I’ve done it on live cables). I am not sure if that can be achieved with an undersea cable as I haven’t worked with such.

Once you have access to the fibers all you need to to do is bend them ever so slightly (they are actually very durable to bending and only break if you use a sharp item on them). By bending them a slight fraction of the transmitted light is able to go trough the coating, then you use a device to measure that light and convert the signal to the appropriate ones and zeros.

MarkH February 25, 2020 12:17 PM


Thanks for your contribution!

We love to make (inadequately|ill|poorly|un)informed speculation here 🙂

It’s most valuable, to hear from people with first-hand experience.

vas pup February 27, 2020 4:05 PM

That is related to tag Russia and subject of the blog – security:
Putin dismisses rumors he uses body doubles for security

“Russian President Vladimir Putin has admitted he was offered the chance to use a body double for security purposes, but rejected the idea.

He said the plan was tabled in the early 2000s, when Russia was fighting a war against separatists in Chechnya.

A 67-year-old former KGB agent, Mr Putin made several trips to the region during the conflict.

For years he has been the subject of conspiracy theories online, including that he uses lookalikes for security.”

There were doubles for Hitler, Stalin, other world leaders – that information was never confirmed by real facts and reliable sources.

If I were President of RF, I’ll probably do the same remembering French history of ‘Iron Mask’ – twin brother of the King and his destiny. When you have double, you put yourself at high risk of being killed and replaced with double by conspirators. Mr.Putin once stated that Throne and Scaffold are always close to each other.

Maxim March 1, 2020 1:55 PM

I believe the capabilities of the Russian special services are greatly exaggerated. The Soviet Union was a serious adversary, but modern Russia is more like a parody of it. The scale of the collapse, theft and degradation are such that we can’t talk about technically complex operations in other countries. The NSA calmly listened to american citizens, before the scandal with Snowden, and no one knew about it. In Russia, a bunch of laws requiring the IT business to provide user data. Those who did not agree – those were blocked. Telegram, linkedin and others. That is, they simply are not able to hack and take information on their own, they need to provide it. So such events at a serious level are most likely simply not feasible.

Jean Paul Neumann March 15, 2020 7:16 AM

The Brazilian Navy monitored for a week a Russian research and intelligence ship suspected of spying in Europe and the United States. The warning signal was lit on the Feb 10th, when the Integrated Maritime Safety Center in Rio de Janeiro detected the Yantar, a vessel with advanced sensor technology, within the Exclusive Economic Zone (EEZ) of Brazil. Soon after a first contact, the ship disappeared from monitoring, raising the hypothesis that the AIS equipment, which allows its location, has been turned off.

yeah! April 13, 2020 4:34 PM

mr. smart cap:

-you are allowed to cheat:

if and only if
russia were at:
-usa’s leasure
-china’s leasure
whitch one of them would/COULD ripp off/rape her?!

now,please check u underwar:where is made IN?!

Ferretjans February 7, 2021 9:01 PM

Im really getting upset of this dam communications war.
Now they build eletrons acelerators, a few people now why, all those billions dollar structures, my guess is, increasing data transfer speed and difficult data tapping, besides they are putting a lot of molecules together to generate new communications patterns, scalating the difficult of reprodution by nations, and that keep and keep going in spiral, to our perplexity of mantaining human corruption in a absurd level.
The tap they are trying to made, must to be external, write this, a live xray scan of optic and mettalic wires, who would can view electrons displacement trough those cables, this already exists, and I bet russians are trying to copy an already politic of…
I just don now who is right, if the quiet corruption of US system or the lowded corruption of Russians, Im just loosing the faith in humanity, all lies, all interests.

Leave a comment


Allowed HTML <a href="URL"> • <em> <cite> <i> • <strong> <b> • <sub> <sup> • <ul> <ol> <li> • <blockquote> <pre> Markdown Extra syntax via

Sidebar photo of Bruce Schneier by Joe MacInnis.