Chrome connects to three random domains at startup

https://mikewest.org/2012/02/chrome-connects-to-three-random-domains-at-startup

by tbassetto • 14 years ago

349 55 14 years ago

I know one thing chrome leaks memory badly in OSX lion, not sure if these magic things happening in background has something to do with it

fourstar• 14 years ago

No wonder I've been seeing youporn.com in my history.

unseen• 14 years ago

Neat feature. In my opinion, they should go even further and make use of the information and inform the user, too:

"Your ISP (network administrator, ..) is intercepting and manipulating DNS requests. Do you want to use Google DNS instead?"

Comes in real handy when we need to have a "DnsManipulationDetector" in the future that checks if your DNS is actively censoring...

dustingetz• 14 years ago

the environments where this is a problem - frequent one-word hosts - are intranets where you want to use the intranet DNS.

codeka• 14 years ago

If your ISP is manipulating DNS like that, it's also possible that they're blocking UDP/53 to any host other than their own DNS servers as well.

Though it's certainly worth a shot, and I suppose Chrome could probably do a test query to 8.8.8.8 before recommending the switch.

RexRollman2• 14 years ago

Some people who probably view that with antitrust concerns, even though I agree that would be a good idea.

gioele3• 14 years ago

> "Your ISP (network administrator, ..) is intercepting and manipulating DNS requests. Do you want to use Google DNS instead?"

I would prefer

"Your ISP (network administrator, ..) is intercepting and manipulating DNS requests. Do you want to install a local caching DNS server and use it instead?"

Unbound [1] is a local DNS server that I have installed on all my machines. Small, fast, security-oriented, IPv6, BSD, made by NLnet Labs.

[1] http://unbound.net/

lmm5• 14 years ago

So you'd install a local caching DNS server that only chrome would use... and this is better than chrome doing its own DNS lookups how?

cydonian_monk3• 14 years ago

I noticed this two years ago, and eventually had to stop using Chrome (and Chromium browsers) as it would result in my ISP blocking all DNS requests from my IP (for a seemingly random amount of time). Even requests to public DNS would fail. It took awhile to identify Chrome as the culprit, and I wasn't convinced after seing the bogus DNS requests in TCP traps. So I started a cycle of using/not using Chrome, and it became obvious.

The easy solution was to stop using Chrome. The hard solution was to move. I've done both, but have yet to start using Chrome again.

kmm• 14 years ago

I don't understand. Why would your ISP block your IP for bogus DNS requests? And why are they monitoring your traffic to public DNS servers? I presume this means they have to look at all traffic that goes over port 53. Is there a security concern?

cydonian_monk3• 14 years ago

I have no idea why they would want to block it, unless they considered it an attack vector for some reason. It was automatic - after a few of the bogus DNS requests, all DNS/port 53 traffic was dropped. Everything else worked, only DNS failed.

brandon• 14 years ago

This is common practice if the queries appear to be originating from worms like Conficker, etc. Others have reported that this behavior of Chrome's can set off false IDS alarms for the same reason.

ohashi• 14 years ago

Can you name the ISP?

cydonian_monk3• 14 years ago

It was originally SBC DSL (resold Yahoo!, resold etc...). The Chrome-induced resolution failures weren't the only issue - their primary DNS server never worked, always went to the failover.

Things didn't improve under AT&T.

njharman• 14 years ago

Your ISP sucks.

subwindow• 14 years ago

This has some interesting ramifications- some network security appliances (I work for a company that makes one) look for suspicious sets of DNS requests that match the Domain Generation Algorithms that malware like Conficker use to find a command and control server.

These "random" requests look almost exactly the DGA for Murofet- a Zeus variant. This has caused some problems for us (and other vendors, I would assume) in the form of massive numbers of false positives. In short, it's been kind of a PITA.

I wish they wouldn't do this, but it is definitely a tough problem to solve and I can't think of a better approach off of the top of my head. The ultimate culprit is the ISPs that return an A record for a DNS request that really should return NXDOMAIN. These ISPs are essentially breaking the Internet, and we're all just scrambling to put band-aids in place to get it to work again.

teach2• 14 years ago

The behavior also causes problems in my workplace, too. I work in a public school, and we use an Internet filter as required by law.

One part of the filter is attached to our default DNS server, and it looks up novel domains to see if they ought to be blocked. This lookup is slow.

Launching Chrome first thing in the morning takes quite a while, because our DNS server/filter blocks until those 3 random domains fail to resolve.

I really wish that I could turn it off, although admittedly our "network" is barely compliant with protocols in the name of filtering.

andrewcooke3• 14 years ago

i suspect that you're using their dns server because it's what is given to you via dhcp, but you can probably configure your own (well, you can certainly configure you own; the problem is it's possible that they are blocking dns requests). for example, set things to use 8.8.8.8 as the dns server (which is google's).

shabble• 14 years ago

It seems like there should be at least some manual override (assuming there isn't one already - I didn't check the details much beyond the article provided) to set your 'my DNS is NX-LYING' flag manually. For machines that are permanently emplaced in a broken DNS network, it can just be turned on and left.

Roaming devices might make it a bit more tricky, but some integration with OS connectivity-detection and location-awareness might help there, as well as an improved UI for actually setting it.

A really short-term bandage would be to use some less identifiable DGA, but that opens the possibility of future malware using the Chrome DGA to pretend to be legit.

Is there a technical reason why 'foo.invalid' and 'bar.invalid' (and any of the other restricted dns names) couldn't be used instead?

I suppose that the ISPs could serve those correctly to make the tests pass, but what would they gain from it except even more user irritation?

Anything I'm missing?

icebraining• 14 years ago

A flag wouldn't be enough, because Chrome also learns what records it returns when it lies, so it can recognize other lies.

jsilence• 14 years ago

This is a good reason not to stick to the DNS-resolver the ISP gives you with DHCP, but to explicitly set it to a DNS resolver you trust.

Wondering why Chrome is not simply using the Google resolver on 8.8.8.8. Of course this would yet be another band aid that breaks the internet even further, when applications start implementing their own network stack.

FooBarWidget• 14 years ago

Not all networks allow using an external DNS. For example I regularly travel with the train in the Netherlands, and some trains provide wifi. The network intercepts all HTTP requests and forwards the user to a Terms Of Usage page; interception stops after the user has checked the 'I agree' checkbox. For a time I was wondering why even the Terms Of Usage page never shows up; turns out it was because I was using the Google DNS. Removing the custom DNS settings made it work again.

st0p2• 14 years ago

We use chrome for internal apps. Forcing you to use 8.8.8.8 means our users have to remember ip addresses instead of http://nameofapplication/

Not a problem for me, but I'm sure a lot of people would complain.

mrb• 14 years ago

There is a big difference between Chrome's requests and Murofet's requests. Chrome uses no TLD ("xxxxx") but Murofet does ("xxxxxx.com").

kamechan• 14 years ago

if you go to chrome://chrome-urls/ and then down to net-internals, you can get a pretty transparent view of exactly what chrome is doing. plus there's a bunch of other stuff there too.

junktest• 14 years ago

chrome://net-internals/#dns

rhplus• 14 years ago

It appears that Chrome aggressively prefetches DNS results for most of the links in pages you visit too. It's quite strange to watch as DNS requested for hundreds of domains you haven't even intended to visit start flowing past. The first time I saw it I had to check that nothing unscrupulous was running on my computer...

iRobot• 14 years ago

.. and a really great reason for using open source programs

basugasubaku• 14 years ago

I'm not sure what you meant by that, but the article does in fact link to the relevant source:

http://code.google.com/codesearch#OAMlx_jo-ck/src/chrome/bro...

skeletonjelly• 14 years ago

That might have been his point - that we were able to find out the reasons why because of it's open source.

clsdaniel• 14 years ago

Interesting, yesterday I moved to a local caching DNS server (much faster and more reliable than what isp provided), however I forgot to set it to run at start up, first thing I do today is try to get to my gmail account, everything is working ok then I try to enter another site, dns lookup error, then I remembered I had named turned off, which means that chrome may have hardcoded google sites ip addresses or is caching them (which is less probable the other site didn't work).

Chrome connects to three random domains at startup

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