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D-Link Firmware Abuses Open NTP Servers
DES writes "FreeBSD developer and NTP buff Poul-Henning Kamp runs a stratum-1 NTP server specifically for the benefit of networks directly connected to the Danish Internet Exchange (DIX). Some time last fall, however, D-Link started including his server in a hardcoded list in their router firmware. Poul-Henning now estimates that between 75% and 90% of NTP traffic at his server originates from D-Link gear. After five months of fruitless negotiation with a D-Link lawyer (who alternately tried to threaten and bribe him), he has written an open letter to D-Link, hoping the resulting publicity will force D-Link to acknowledge the issue. There are obvious parallels to a previous story, though Netgear behaved far more responsibly at the time than D-Link seem to be."
From TFA: "A number of D-Link products, so far I have at least identified DI-604, DI-614+, DI-624, DI-754, DI-764, DI-774, DI-784, VDI604 and VDI624, contain a list of NTP servers in their firmware and using some sort of algorithm, they pick one and send packets to it."
NTP server use is tiered. So client PCs are not supposed to hit the tier 1s, they should hit 2nd tier or a local ntp server.
You don't use the root DNS servers for all your DNS requests, right?
Yes, you're confused. And, you didn't read the article. The author is pissed because he's running an NTP server intended to be accessed only by Danish networks, and for use by servers, not clients. D-Link products are only marketed to clients, and not just Danish clients.
...phil
"For a list of the ways which technology has failed to improve our quality of life, press 3."
If there's one thing I hate more than incompetence, it's people who don't care that they are incompetent and carry on churning out crap regardless of the problems it causes others.
According to this page, D-Link have an office operating in Denmark. This makes them subject to Danish law whether they like it or not. I don't know whether Denmark's computer crime laws cover this, but it wouldn't surprise me.
Bogtha Bogtha Bogtha
He says that such a solution is hard to implement on Cisco, and would be too CPU intensive. FTFA: "Filtering the D-Link packets requires inspection of fields which are not simple to implement in Cisco routers, and in particular such filtering seems to send all packets on the interface through the CPU instead of fast switching, so ingress filtering the packets at the ingress of AS1835 is totally out of the question."
The pool guys have been talking of implementing a $company_name.vendor.ntp.pool.org setup. Having the $company_name specificity would allow them some leeway if an individual vendor does something silly. I don't know if any vendors have bought into this though.
He hosts a NTP server with the intention of it being used by a certain audience. He's not pissed people outside of that audience are using the server, he's pissed that D-Link decided to abuse the service he's providing and now the overwhelming majority of the people using his service are outside the intended audience.
Sorta like how server admins get pissed when an article posted on their site causes them to be Slashdotted.
And honestly, the fact that D-Link is acting in the way it is while he trys to get them to resolve the issue probably isn't helping matters.
Then again, as a former owner of a D-Link product which rebooted itself anytime I went over 50 simultaneous connections (think P2P), I don't doubt they'd be too cheap to actually just run their own.
A good idea, but not easily doable, since the allowed networks include most of Denmark. He would have to filter traffic based on the AS of the sender; this would require a full BGP feed and probably also a continuously updated mirror of the RIPE database.
Sorry to correct your rant, but he does say in TFA that the offer was so low that it didn't even cover his costs. That would be a good enough reason to say no wouldn't it?
That was Belkin.
Let me clarify a number of details here.
1. My server has not replied to the packets sinde the CodeRed virus/worm abused NTP servers to coordinate attacks. That was a couple of years ago. I doubt D-Link ever even tried to test this.
2. NTP is a timing protocol. You do not want to do expensive and timeconsuming filtering on the packets because that disturbs your timing performance.
3. If I have to sue D-Link, it will be either in USA or Taiwan. Both their Danish marketing office and the UK european office will be able to deflect a lawsuit to their mothership.
4. If you download a firmware file from D-Link, it is often a ARJ archive. unpack that and run strings. If you see GPS.dix.dk in there, please use another version. If the firmware you run is older than about a month, please update it.
5. The list of products in my open letter is unlikely to be complete, those are the only ones I have been able to positively identify (using the method above). If you find out other products are affected, please email me.
6. We do have a number of very interesting sections of our penal code here in Denmark that are very likely to apply. Only problem is, they havn't been tried in a court yet. So I have to persuade an overworked criminal inspector to raise a criminal case against a foreigner over a, lets face it, quite small monetary amount. Then I have to spend a lot of time making sure that we convince a judge who have never heard of NTP that they are guilty and then if I win, I can see some D-link manager make a checkmark in their pocket book: "Remember to not visit Denmark under true name". I have better things to use my life for.
I can see a couple of hits from a C-class belonging to "D-Link Irwine": please escalate this guys, your bosses don't read slashdot.
Thanks for all the supportive email.
Poul-Henning
Poul-Henning Kamp -- FreeBSD since before it was called that...
No, he can't "just firewall the server" and "tell the few people that would affect". There are thousands of legitimate users distributed across thousands of ASes covering thousands of IP ranges which may change from day to day or even hour to hour. His server is directly connected to the core switch at the Danish Internet Exchange, where all major Danish networks exchange BGP routing information and domestic IP traffic, and its purpose is to provide a stratum-1 reference for NTP servers on these networks. To determine which IP ranges may legitimately access his server, he would need a full BGP feed and a continuously updated copy of all as-block and aut-num records in the RIPE database.
Now that you look at your ethernet sniffs (I assume you just went running off and ran ethereal) look at the source ethernet address... Hmmmmm - doesn't that look familiar, like maybe it looks kinda like your first hop routers MAC address.
Nice try -
Thank you, Come Again
And please read either Stevens or Comer before posting on networking topics again
I have mod points and I am not afraid to use them
Someone else replied, but let me actually EXPLAIN.
pool.ntp.org is a collection of volunteer NTP servers, served up via DNS. You should not expect to get meaningful results from pointing a Web browser at such a host name, but because it is random, you could end up hitting Amazon.com (assuming they volunteered) or some guy that just set up an Apache server.
http://www.pool.ntp.org/ is what you meant, as a simple google search for "pool ntp" would have told you.
Right, because lawyers are cheap... right.
I like how he doesn't mention any numbers.
He already has dedicated hosting, do they charge him $1 per megabyte or something?
If you'd bother to RTFA, once again, he answers how much the hosting is costing him. He talks about numbers all over the place.
" because I offer this service free of charge and NTP is a low bandwidth protocol, the organization behind the DIX has graciously waived the normal DKR 27.000,00 (approx USD 4,400) connection fee."
" the current theory is that I will have to close the GPS.DIX.dk server or pay a connection-fee of DKR 54.000,00 (approx USD 8,800) a year as long as the traffic is a significant fraction of total traffic to the server."
" I owe $5000 to an external consultant who helped me track down where these packets came from."
" I have already spent close to 120 non-billable hours (I'm an independent contractor) negotiating with D-Link's laywers and mitigating the effect of the packets on the services provided to the legitimate users of GPS.dix.dk."
" Finally I have spent approx DKR 15.000,00 (USD 2,500) on lawyers fees trying to get D-Link to negotiate in good faith."
" If I closed the GPS.dix.dk server right now, wrote off all the time I have spent myself, then my expenses would amount to between DKR 45.000,00 and DKR 99.000,00 (USD 7,300 to 16,000) and several hundered administrators throughout Denmark would have to spend time reconfiguring their servers.
If on the other hand we assume I leave the service running and that the unauthorized packets from D-Link products continue for the next five years, the total cost for me will be around DKR 115.000,00 + 54.000,00 per year (approx USD 18,500 + USD 8,800 per year) or DKR 385.000,00 over the next five years (USD 62,000). " block the NTP traffic from anything outside his network if it is sooooo expensive for him. You can do that at the ISP level in most cases.
He also mentions how blocking traffic is not feasible, and why, IF YOU'D BOTHER TO READ THE FUCKING ARTICLE. Learn how to read or STFU about him being an asshole.