131–140 of 157 posts
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How so?
Because it is MY source code, I don't want to send it anywhere. (Yes I do use GitHub/Bitbucket, only for public code)
Ethically, and morally, requiring the source to be available might be good.
Wait.. they are saying the app itself is making NTP requests? > Confirmed - starting up the iOS Snapchat app does a lookup to the domains you listed, and then sends NTP to every unique IP. Around 35-60 different IPs. Hmm. Is that a fraud prevention thing or something? No way on earth a user app should be getting its own time
This practice is becoming increasingly common for "time-sensitive applications":
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Right, the DNS records weren't expired, they were no longer accurate. I'm not sure what the word for that is. The Windows DNS Cache on the local machines was inaccurate. Basically, I couldn't access any websites I had accessed before, but if I tried accessing a new site it worked fine. If I forced a DNS request for a site I had already visited, that site would start working but all the other sites would still be brok…
It's called the resolver cache, and Linux does it too. Most commonly with nscd (use "nscd -i hosts" to clear it, keep in mind this is not specific to DNS requests). In the specific situation of a web browser it's more complicated and you'll find that the web browser caches these things too. If you run Chrome check out chrome://net-internals to get a glimpse of what's going on there.
I know Chrome in Linux definitely doesn't cache DNS requests. I believe Linux only keeps the DNS info around until the socket closes, but I don't know the actual implementation. I looked in to the ncsd man page, and it looks like DNS info isn't cached, only open sockets.
I know Chrome uses the system DNS cache in Windows, and my understanding was that all browsers in Windows used the system DNS cache.
I don't know a lot about how sockets are handled. I thought they were discarded as soon as they were closed, but they could function similarly to a DNS cache. I though a DNS cache stuck around for a lot longer though.
FWIW my teenage daughter has been complaining about this latest Snapchat update for iOS the past couple days. It constantly crashes and causes the phone to reboot itself. Looking at Twitter, there's tons and tons of people reporting the same issue, so it seems pretty widespread. Wonder if it's related to this NTP issue.
Can apps cause iOS to reboot ? That's a bit shocking. I don't own an iPhone.
Wait.. they are saying the app itself is making NTP requests? > Confirmed - starting up the iOS Snapchat app does a lookup to the domains you listed, and then sends NTP to every unique IP. Around 35-60 different IPs. Hmm. Is that a fraud prevention thing or something? No way on earth a user app should be getting its own time
I've never used Snapchat but I believe one of its features is time-expiring photos. If they do the expiration in the client then this may be a way to check if a user is getting around it by setting the system clock backwards.
Ironically, part of an HTTPS handshake involves sharing the server time in a cryptographically-verifiable manner. I am not sure why they don't use that! https://github.com/ioerror/tlsdate
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Yes, but when your IT is incompetent they do the first half (block NTP to anywhere outside your network), then don't provide their own time source. Then try to blame users when they complain that their time is always wrong.
We do have our own time source. Our NTP source is locked to that server via GPO. NTP requests aren't blocked, because I can still set NTP on things like my printer to other NTP sources and receive updates. I'm willing to bet they don't realize that they've blocked their server. What I want to know is how the drift got to be this bad in a matter of days. It's like whatever computer they are using as the NTP server doe…
It sounds like their domain controller holding the PDCE FSMO role is a virtual machine. This advice might be outdated but last time I checked it was better to host it on a physical machine. If they're restoring DBs from backups without notifications and managing their Active Directory environment like this I can only imagine how fragile your infrastructure really is. Good luck, you're going to need it.
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Can apps cause iOS to reboot ? That's a bit shocking. I don't own an iPhone.
I've seen a test version of an app cause issues such that the launcher would crash (i.e. "respring"). Probably some intersection of particular api usage and OS bugs. To the unobservant user it looks like the OS is rebooting, although it's much quicker than a real reboot.
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I'm guessing of cause, but it's entirely possible that they used the ntp.org pool, because that's what a quick Google search would tell you to do. Getting a vendor zone require that you know it exists.
> I'm guessing of cause, (...) they used the ntp.org pool, because that's what a quick Google search would tell you to do You're wrong, see my upper comment in this very thread, I've wrote already: they used the third-party library which has as default in the call without any arguments the huge number of the ntp.org servers. The servers hit and the servers in the library sources match exactly. They used that default,…
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It's called the resolver cache, and Linux does it too. Most commonly with nscd (use "nscd -i hosts" to clear it, keep in mind this is not specific to DNS requests). In the specific situation of a web browser it's more complicated and you'll find that the web browser caches these things too. If you run Chrome check out chrome://net-internals to get a glimpse of what's going on there.
Thanks for the tip on net-internals. I think I used a similar feature in Firefox a long time ago, but I've never used this tool in Chrome before. I know Chrome in Linux definitely doesn't cache DNS requests. I believe Linux only keeps the DNS info around until the socket closes, but I don't know the actual implementation. I looked in to the ncsd man page, and it looks like DNS info isn't cached, only open sockets. I…
Guess I know why now..