Hunting for North Korean Fiber Optic Cables

https://nkinternet.com/2025/12/08/hunting-for-north-korean-fiber-optic-cables/

by Bezod • 8 months ago

289 106 8 months ago

nkinternet.com

superducktoes3• 8 months ago

Thanks for sharing my site. Happy to answer any questions

monerozcash5• 8 months ago

Don't have questions, but your blog is very cool.

A bit over a decade ago I used to spend a lot of time hacking North Korean web infrastructure, I mostly found that they tended to have firewalling around almost all boxes exposed to the global internet and usually had pretty impressive reaction times if you tried to access the country intranet through a compromised web server.

I've always wondered how successful NSA and the likes have been at infiltrating DPRK networks, as it would inherently be fairly easy to detect any sketchy traffic from the outside. I wonder if the recent NYT story essentially confirms that difficulty.

Regarding the NSA and DPRK, there's this document from 2007 least https://www.eff.org/files/2015/02/03/20150117-spiegel-fifth_...

I guess I have a question after all: I'm not exactly clear on how NK treats end-user devices. Do you know if the endpoints used by NK based remote workers have internet and intranet access at the same time? If they do, such an endpoint could offer an easy and stealthy channel to access the intranet.

superducktoes3• 8 months ago

thanks really appreciate that! I've seen that doc before and it does really make me wonder. part of the leaks from the NSA tools years back had some references in there for detecting north koreas ant-virus silivaccine

https://github.com/b30wulf/Malware-collection/blob/4f5906c93...

There was also the hacking team leak from years ago and they were selling exploits for north korea's red star OS: https://nkinternet.wordpress.com/wp-content/uploads/2025/12/...

I assume they've been on their networks in the past but i think North Korea has also done a lot over the years to secure their side. it used to be a lot easier when they left everything as an open directory and didn't realize what they were doing.

superducktoes3• 8 months ago

the end user devices are also really interesting. as far as i know they require a piece of software called netkey or oconnect as it's recently been renamed. that's for getting access inside the country and then for anyone outside they have software called hangro that is similar to a vpn for connecting back to north korea and getting messages

anonu• 8 months ago

this document from 2007

Interesting document - confirming "everyone spies on everyone". Is this from some sort of corporate NSA chat room?

metadat• 8 months ago

Impressive sleuthing!

It's interesting to discover the reality that packet routing ends up following political affiliations. I didn't know North Korea only has 1,024 IPv4 addresses. Do you know why so few IPs? How did they get them?

monerozcash5• 8 months ago

DPRK can certainly get however many IP addresses they want, DPRK just doesn't have that much infrastructure that they want externally accessible.

As far as I know, end-user traffic from within North Korea usually does not originate from those few IP addresses. Or at least not visibly so, they might be connecting to a proxy from a DPRK IP address.

toast02• 8 months ago

It's interesting to discover the reality that packet routing ends up following political affiliations.

Certainly political affiliations have some influence, but also China and Russia have land borders with North Korea and are not at war. It's very common to run fiber optic on/under railroads and vehicle roads, so there you go. It's probably pretty hard to attract an international cable consortium to land in North Korea given everything, but terrestrial cabling is easier to start with anyway.

I didn't know North Korea only has 1,024 IPv4 addresses. Do you know why so few IPs? How did they get them?

They would have asked APNIC, the Regional Internet address Registry for their region (Asia-Pacific). I can't find an assignment date, but 175/8 was assigned to APNIC in 2009. 2009 lines up with wikipedia reporting of the startup of the current ISP joint venture.

apercu• 8 months ago

What a great read. Thanks.

eqvinox5• 8 months ago

… 2.5 GB per second between all the provinces.

What's your source for that number? Is it GBit or GByte? Are they building out OTU1?

liversage• 8 months ago

My understanding is that there are three mobile networks in North Korea: the normal one used by the citizens (they have smartphones made specifically for North Korea), one used by the government/military and one for tourists (requires a local SIM card only available in a specific hotel in Pyongyang).

The last one is connected to the internet and this is why you can see (or at least before the pandemic could see) Instagram posts from North Korea.

I have no idea if this information is still or ever was completely true though.

There's a somewhat dated but very interesting AMA on Reddit by an American teaching computer science in Pyongyang:

https://www.reddit.com/r/IAmA/comments/1ucl11/iama_american_...

Reading about the internet knowledge possessed by North Korean students, I'm always surprised how they supposedly also manage to be some of the most cunning and evil actors when it comes to hacking.

foota• 8 months ago

Re: "I'm always surprised how they supposedly also manage to be some of the most cunning and evil actors when it comes to hacking."

I sort of suspect this is just the result of a nation state that is willing to be a pariah. That is, I think nearly any large state could do it if they didn't mind burning bridges.

louthy• 8 months ago

It’s not just that they don’t care about being a pariah state, it’s a literal fund raising exercise, unlike most other state sanctioned hacking.

ipdashc• 8 months ago

This is my assumption as well. In general it seems like hacking becomes a lot easier (still not easy of course, just easier) when you have no fear of getting caught or going to jail.

Does anyone remember LAPSUS$ https://en.wikipedia.org/wiki/Lapsus$ from a while back? It was reported for a while that it was largely made up of teenagers, and it seems two did get caught. I recall their whole MO being brazen social engineering/using stolen credentials in a way that got them caught pretty quickly, but also got results fast.

Atlas667• 8 months ago

"Pariah", they've had the longest embargo on earth (which has caused hundreds of thousands of deaths), they had 90% of their whole countries infrastructure bombed by the US, and the Korean war has been called a genocide in the North by many scholars.

The world doesnt make sense if you ignore history.

They probably hack for the same reason the west does it: attack/defense and money.

wongarsu• 8 months ago

See also Russian hackers being notorious simply because Russia is willing to turn a blind eye to cyber crime that doesn't target Russia

Crime being illegal doesn't prevent crime, but it adds an enormous amount of friction. In the West if you are decent at hacking, low-level APIs or reverse engineering you could turn to cyber crime. But if you instead get a regular job in cyber security or software engineering you still get a good salary, and don't have to worry about your online friends being police informants, can tell your potential significant other what you do to earn a living, get money wired directly to your bank account instead of having to go through costly intermediaries with significant risks, don't have trouble with the tax authority, etc.

If you reduce the legal opportunities and remove the downsides of the illegal ones the calculation completely changes, and with it the talent pool

seized• 8 months ago

Probably helps that the stance is likely "Hack this target or your family dies". That's always pretty uhhhh motivational.

engineer_22• 8 months ago

Maybe they hire international talent.

AngryData9• 8 months ago

Why would they need such incentives? All they gotta do is give them a decent wage and they will be happy, which in North Korea is a paltry sum. Its not like regular North Koreans are traveling around the world, they couldn't afford it even without any other restrictions, so they have zero risk of arrest or punishment from other nations.

If I told you today that I will pay you a million dollars to go fuck around with some North Korean servers, and doing it completely anonymously with the full protection and sanction of your government, would you say no?

I think you may have some unrealistic views on how North Korea operates internally. 99% of their population lives completely normal lives and has zero extra interactions with the government beyond basic grunt military service which is common across much of the world, and paperwork for licensing, permits, and taxes. We only see the worst possible views of North Korea from the outside, slathered with thick layers of additional propaganda on top of it.

hulitu3• 8 months ago

That's always pretty uhhhh motivational

If you only met the world on American TV, yes.

supernetworks• 8 months ago

tragically, this is exactly what it is

mmsc• 8 months ago

one for tourists (requires a local SIM card only available in a specific hotel in Pyongyang).

I do not think that exists. I imagine the diplomats and other foreigners living there will have this, though.

When I was there two times (in Pyongyang, and in villages in the north east & Rason) any access to the outside world was prohibited via a network other than telephone (I could make outgoing phone calls via the hotel). Even traveling very close to the border (which they use jammers to block outside connections), my guides were annoyed when they saw I was trying to connect to the Chinese network from my phone.

The only place I saw any access "to the outside world" was in Rason (https://en.wikipedia.org/wiki/Rason_Special_Economic_Zone), where one of the casinos had a computer which could be used to access the internet (through the Chinese GFW, of course).

piokoch• 8 months ago

"I'm always surprised how they supposedly also manage to be some of the most cunning and evil actors when it comes to hacking"

This sentiment is probably overblown. The fact that they are effectively robbing people to earn some money for their pathetic regime means only that they are on the level of nowadays internet scammers. They are good at that too.

Spending enough money (and they spend a lot - 26 million people work only for this) one can train people to do this or hire people to do this for them.

mikkupikku• 8 months ago

Do those small utility boxes alongside the tracks make sense for fiber optic? I expected things like that to be larger, if only because fiber has a minimum bend radius.

Edit: Good article though, I enjoyed it a lot.

adamcharnock• 8 months ago

The min bend radius isn’t that large in my experience. On the order of 10cm IIRC, possibly even less.

st_goliath• 8 months ago

Much smaller than that, some might even say a utility box is overkill: https://old.reddit.com/r/techsupportgore/comments/nvwcuh/the...

Lukas_Skywalker• 8 months ago

Even less is correct: outdoor fibers (G.652.D) have a minimum bend radius of about 30mm. The indoor counterpart (G.657.A1 and A2) have 10mm and 7.5mm.

mikeyouse• 8 months ago

Fiber’s perfectly happy being joined in 12” by 16” boxes for small runs. The terminal box in my garage has a few loops and is more like 6” x 8”.

https://www.seeclearfield.com/fiber-optic-wall-box/metal-wal...

whatsupdog• 8 months ago

Railroad minimum bend radius is orders of magnitude bigger than fiber's.

codedokode• 8 months ago

Isn't it easier to hang optic cable on the poles? It seems that burying the cable requires more work.

As for utility boxes along the track, it could be something railway-related, for example, some railway control or monitoring equipment.

samus• 8 months ago

They are too vulnerable to the elements there.

actionfromafar• 8 months ago

A few inches of dirt protects against cables darkening from nuclear blasts, if you care about that sort of thing.

bigiain2• 8 months ago

If you hang your fibre optic cable from poles, you will inevitably evolve flying backhoes.

eqvinox5• 8 months ago

Too late, already happened, it's called squirrels. cf. CCC NOC logo: https://events.ccc.de/camp/2019/wiki/Static:Network — it's an in-joke about rodents chewing through the (air/tree-strung) uplink fibre multiple times at the 2015 event.

AngryData9• 8 months ago

It is easier, but it is also far more vulnerable and won't last nearly as long.

eqvinox5• 8 months ago

Yes, poles are standard practice in a lot of places, but not generally for backbone links. There's only a few of those and it makes sense to get the extra protection from burying them.

Also, installing general telco fibre next to railway lines is standard practice. Makes all the bureaucracy so much easier if you can just use the existing railway right-of-way. Not that the DPRK would care much about right-of-way ;D

dboreham• 8 months ago

I found the railroad part of the article unpersuasive. Optical repeater stations are fairly large and therefore wouldn't show up as random small underground vaults or little boxes on poles. These look like a collection of pictures of train tracks with no particular indicators of optical cables therein.

petcat4• 8 months ago

Can we back up and just recognize how insane North Korea is? I think that future generations will look back on our history and wonder why nobody ever did anything about the incredible atrocities that took place in that country for decades.

VWWHFSfQ• 8 months ago

It will definitely go down as one of the biggest failures of mankind. Especially since it was so easily preventable if MacArthur was permitted to just take the whole peninsula.

antonymoose• 8 months ago

Think how many tens of millions could have been saved if we had ended the Soviet Union as Churchill advocated, before the world got nukes.

timschmidt2• 8 months ago

China was already sending troops and material to the front lines when MacArthur was ordered to stand down. Pushing further would have meant a hot war with China.

etc-hosts2• 8 months ago

You know the US destroyed nearly 75 percent of all buildings in North Korea during the Korean War, right?

NK is paranoid for very valid reasons.

AngryData9• 8 months ago

Or how about us not blowing them to bits in the first place? South Korea was on the very edge of capitulation before the US came in full force and even most South Korean citizens were in support of Korean unification at that time. The current state of North Korea would have never come to reality if they hadn't been blown to bits by the US because of big ol' scary "communism".

nephihaha• 8 months ago

North Korea is a buffer state and continues to exist because of China.

joecool1029• 8 months ago

I will get buried for saying this, but DPRK survived as a people, investing everything into a nuclear program to survive. The reason nobody did anything is they firmly built a defense against intervention, and given how the korean war went, how various US interventions looked after that, it was the correct thing to do. The most the US could do to them in recent years was murder some innocent fishermen. It has tried to starve them and failed.

jojobas7• 8 months ago

s/DRPK survived as a people/Kim dynasty survived in power/g.

Sure it was a correct thing for Kims to do, millions of Koreans be damned.

AngryData9• 8 months ago

Except we aren't blameless either for the state North Korea ended up in. We leveled nearly every building in the country, we even targeted rural thatch huts with bombing runs. We dropped so many bombs on North Korea that the bombers started dropping bombs on thrice bombed rubble and open land because they couldn't find any targets left to attack. Why should we be surprised that a strong arm authoritarian leadership rose up among the chaos and put every effort towards military power and obtaining nuclear weapons at the expense of everything else?

I can't even say that they made the wrong decision either, North Korea still exists as an independent nation which is amazing in itself.

TheBicPen3• 8 months ago

At least NK's human rights abuses are contained within their borders. I hope future generations will look back on the many US invasions of foreign countries over the years and all the war crimes that took place during those invasions with the scrutiny they deserve.

rexpop• 8 months ago

Is this how we are to attribute atrocities? Where does the buck stop?

hulitu3• 8 months ago

why nobody ever did anything about the incredible atrocities that took place in that country for decades.

Why in that country ? US controls much of western opinion and made a lot of atrocities, yet, nobody cares (see the ongoing https://en.wikipedia.org/wiki/2025_United_States_military_st... )

keybored• 8 months ago

People scoff at North Korean propaganda.[1] Then they turn around and say this with a straight face.

America bombed North Korea back to the stone age. Now we in the West wonder why it’s so F’d up by its very own volition.

[1]: This is not to say that North Korean propaganda is not real.

edm0nd• 8 months ago

a random interesting fact:

North Korea is responsible for adding the hot beverage, umbrella with raindrops, and lightning bolt emojis

https://en.wikipedia.org/wiki/KPS_9566

metalman• 7 months ago

high voltage transmission lines can and are built with a glass fibre core, and would be essentaily invisible

also a ditch witch and couple of support vehicles could run cable through most terrain, and in agrairian areas , not needing permits and such, would be indistinguisashable from other activity ,happen very quickly, and leave no trace

humanity has reached the point where our comunications net is a given for 90%+ of the population centers in one form or another, and if not for the slop, would have an order of magnitude, excess capacity. throw in peer to peer ,and the soon to be blanket coverage from sattelite swarms, and well, what? sonar relays for underwater, and seizmo transmitters

Hunting for North Korean Fiber Optic Cables

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