4 ms·

Recently I have been getting a request from chrome for access to local network devices. I can’t figure out which site I’m visiting is doing this, because the re

Recently I have been getting a request from chrome for access to local network devices. I can’t figure out which site I’m visiting is doing this, because the request doesn’t specify which tab. I would LOVE a little icon for something like that.

emctech 1mo ago
ebay does this i think, someone else linked a post about port scanning
bartread 1mo ago
Yeah, that’s always an automatic nope. No explanation of who/what is really asking or why so, no: your shit software or website can’t go snooping around on whatever network I happen to be on, whether that’s at home or at work.
mohaine 1mo ago
pretty sure it is a way of fingerprinting your machine/network
- RajT88 1mo ago
  Let's hope it's as simple as that and not a malvertising campaign.
RajT88 1mo ago
Chrome says "this site", no? Isn't it the tab you have in focus? I wonder what kind of person says 'Yes' to this prompt. It gives me the heebie jeebies.
- auxiliarymoose 1mo ago
  3D mice and other hardware may run a local server for web applications to use them as input methods. The dialog can also show up if you are using network security software which proxies requests via private IP address range. Plenty of other non-nefarious reasons too... Safari and Firefox allow this by default without a prompt or visible indicator (but maybe that has changed now that Chrome added its dialog).
- VladVladikoff 1mo ago
  No, it’s a macOS level prompt.
  - lxgr 1mo ago
    Then it’s most likely Chrome using local network access for WebRTC or Chrome without granting that access to websites without any explicit interaction with camera permissions or cast features.
lxgr 1mo ago
Any chance it was a macOS prompt? Chrome needs local network permissions for WebRTC, Cast etc. even without any website accessing your local network.
- dwaite 1mo ago
  It is most likely this: https://wicg.github.io/local-network-access/ https://wicg.github.io/local-network-access/ For a while there's been an anti-pattern where a piece of software leaves a localhost daemon running (often without proper security) for web integration. One of the more famous abusers was Zoom: https://infosecwriteups.com/zoom-zero-day-4-million-webcams-maybe-an-rce-just-get-them-to-visit-your-website-ac75c83f4ef5 https://infosecwriteups.com/zoom-zero-day-4-million-webcams-... XSRF vulns also have existed where e.g. a web page can blinding attempt to hit your router's page to change your DNS servers by knowing common router admin sites and default home network topologies. This isn't as useful in today's HTTPS world. Browsers have been adding more partitioning between local and internet resources to prevent this sort of thing. But that does mean simply putting localhost entries in a hosts file to blackhole a site can now cause an issue.
MattGrommes 1mo ago
Something in my work's SSO / auth mechanism does this and if you click No it silently screws up the internal website you're visiting. It doesn't block you from logging in, just parts of the site don't load/work. I haven't been able to get a good answer on what the heck is going on but it's extremely annoying.
RetpolineDrama 1mo ago
I had this and it turned out to be my unifi firewall block triggering a false-positive in the browser.
announcer4614 1mo ago
Are you running PiHole, Adguard or similar and using macOS? On macOS, Chrome treats 0.0.0.0 as a local address which results in these prompts. Switching to having blocked domains return NXDOMAIN can work around the issue.
- VladVladikoff 1mo ago
  Thanks! Could be AdGuard!
javier2 1mo ago
usually its scanning for chromecasts on the local network, but could be other things as well
derefr 1mo ago
I would note that if you say no to this, not only automatic but also explicit top-level navigation to “local network” locations (e.g. localhost, 192.168.1.x, etc) will be denied. Kind of annoying when you don’t want Chrome exploring your network, yet still need to regularly e.g. access your NAS web dashboard.

emctech 1mo ago

ebay does this i think, someone else linked a post about port scanning

bartread 1mo ago

Yeah, that’s always an automatic nope. No explanation of who/what is really asking or why so, no: your shit software or website can’t go snooping around on whatever network I happen to be on, whether that’s at home or at work.

mohaine 1mo ago

pretty sure it is a way of fingerprinting your machine/network

RajT88 1mo ago
Let's hope it's as simple as that and not a malvertising campaign.

RajT88 1mo ago

Chrome says "this site", no? Isn't it the tab you have in focus? I wonder what kind of person says 'Yes' to this prompt. It gives me the heebie jeebies.

auxiliarymoose 1mo ago
3D mice and other hardware may run a local server for web applications to use them as input methods. The dialog can also show up if you are using network security software which proxies requests via private IP address range. Plenty of other non-nefarious reasons too... Safari and Firefox allow this by default without a prompt or visible indicator (but maybe that has changed now that Chrome added its dialog).
VladVladikoff 1mo ago
No, it’s a macOS level prompt.
- lxgr 1mo ago
  Then it’s most likely Chrome using local network access for WebRTC or Chrome without granting that access to websites without any explicit interaction with camera permissions or cast features.

lxgr 1mo ago

Any chance it was a macOS prompt? Chrome needs local network permissions for WebRTC, Cast etc. even without any website accessing your local network.

dwaite 1mo ago
It is most likely this: https://wicg.github.io/local-network-access/ https://wicg.github.io/local-network-access/ For a while there's been an anti-pattern where a piece of software leaves a localhost daemon running (often without proper security) for web integration. One of the more famous abusers was Zoom: https://infosecwriteups.com/zoom-zero-day-4-million-webcams-maybe-an-rce-just-get-them-to-visit-your-website-ac75c83f4ef5 https://infosecwriteups.com/zoom-zero-day-4-million-webcams-... XSRF vulns also have existed where e.g. a web page can blinding attempt to hit your router's page to change your DNS servers by knowing common router admin sites and default home network topologies. This isn't as useful in today's HTTPS world. Browsers have been adding more partitioning between local and internet resources to prevent this sort of thing. But that does mean simply putting localhost entries in a hosts file to blackhole a site can now cause an issue.

MattGrommes 1mo ago

Something in my work's SSO / auth mechanism does this and if you click No it silently screws up the internal website you're visiting. It doesn't block you from logging in, just parts of the site don't load/work. I haven't been able to get a good answer on what the heck is going on but it's extremely annoying.

RetpolineDrama 1mo ago

I had this and it turned out to be my unifi firewall block triggering a false-positive in the browser.

announcer4614 1mo ago

Are you running PiHole, Adguard or similar and using macOS? On macOS, Chrome treats 0.0.0.0 as a local address which results in these prompts. Switching to having blocked domains return NXDOMAIN can work around the issue.

VladVladikoff 1mo ago
Thanks! Could be AdGuard!

javier2 1mo ago

usually its scanning for chromecasts on the local network, but could be other things as well

derefr 1mo ago

I would note that if you say no to this, not only automatic but also explicit top-level navigation to “local network” locations (e.g. localhost, 192.168.1.x, etc) will be denied. Kind of annoying when you don’t want Chrome exploring your network, yet still need to regularly e.g. access your NAS web dashboard.