[HN Gopher] Hunting for North Korean Fiber Optic Cables
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       Hunting for North Korean Fiber Optic Cables
        
       Author : Bezod
       Score  : 185 points
       Date   : 2025-12-08 16:38 UTC (6 hours ago)
        
 (HTM) web link (nkinternet.com)
 (TXT) w3m dump (nkinternet.com)
        
       | superducktoes wrote:
       | Thanks for sharing my site. Happy to answer any questions
        
         | monerozcash wrote:
         | 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.
        
           | superducktoes wrote:
           | 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.
        
             | monerozcash wrote:
             | >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/...
             | 
             | South Korean NIS was in fact a hacking team client, so it
             | would make sense. Especially considering how terrible Red
             | Star OS was at the time, a HT engineer could probably have
             | whipped those up in a couple of days.
             | 
             | https://web.archive.org/web/20180302155452/http://english.y
             | o...
             | 
             | >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.
             | 
             | I'm sure they've had _some_ success, but I 'd expect it to
             | be a really difficult environment to operate in. Even for
             | the NSA. I suppose eventually there'll be a better leak and
             | we'll get to find out just how well it's been going.
        
           | superducktoes wrote:
           | 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
        
         | metadat wrote:
         | 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?
        
           | monerozcash wrote:
           | 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.
        
             | lukan wrote:
             | "DPRK can certainly get however many IP addresses they
             | want"
             | 
             | IP4 is quite limited as far as I know and not given out
             | freely since a long time, or what do you mean here?
        
               | jauer wrote:
               | IPv4 continues to be available to entities that have a
               | need that fits a particular policy shape, just most
               | people don't. Specifically, you can get IPv4 /24s for
               | IPv6 transition purposes. This includes anycast DNS, MX,
               | etc for legacy clients on other networks, v4-side of
               | CGNAT, etc.
               | 
               | E.g. I was able to get a /24 in the ARIN region in 2021
               | and could justify 2 more for a _logical_ network topology
               | similar to what NK presents to the world.
               | 
               | APNIC similarly has a pool available for IPv4
               | allocations: https://www.apnic.net/manage-
               | ip/ipv4-exhaustion/#the-situati...
        
               | monerozcash wrote:
               | IPv4 is readily available and not very expensive. DPRK
               | can just buy or lease them.
        
               | toast0 wrote:
               | APNIC has some addresses [1] and will assign up to two
               | /24s to qualified new accounts within the region. There
               | are also carve outs for National Internet Registries and
               | Internet eXchange Points.
               | 
               | [1] as of Nov 2025, approximately 3 million or a little
               | more than 12,000 /24s https://www.apnic.net/manage-
               | ip/ipv4-exhaustion/#how-to-tras...
        
           | toast0 wrote:
           | > 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 wrote:
         | What a great read. Thanks.
        
       | liversage wrote:
       | 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 wrote:
         | 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 wrote:
           | 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.
        
       | mikkupikku wrote:
       | 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 wrote:
         | The min bend radius isn't that large in my experience. On the
         | order of 10cm IIRC, possibly even less.
        
           | st_goliath wrote:
           | Much smaller than that, some might even say a utility box is
           | overkill: https://old.reddit.com/r/techsupportgore/comments/n
           | vwcuh/the...
        
           | Lukas_Skywalker wrote:
           | 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 wrote:
         | 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...
        
       | codedokode wrote:
       | 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 wrote:
         | They are too vulnerable to the elements there.
        
       | dboreham wrote:
       | 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.
        
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       (page generated 2025-12-08 23:00 UTC)