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Ask HN: Why does the US Visa application website do a port-scan of my network?
I have recently installed this extension on FF: https://addons.mozilla.org/en-US/firefox/addon/port-authority/ https://addons.mozilla.org/en-US/firefox/addon/port-authorit... and yesterday I visited this website: https://ceac.state.gov/genniv/ https://ceac.state.gov/genniv/ and I got a notification that the website tried to do a port-scan of my private network.
Is this a common thing? I have just recently installed the extension, so I am not sure if there are a lot of other websites who do it.
Since looking into it, I noticed that uBlock Origin already has the default list "Block Outsider Intrusion into LAN" but it wasn't enabled.
- Maxious 1y agoPerhaps to avoid people using misconfigured open proxies https://en.wikipedia.org/wiki/Open_proxy https://en.wikipedia.org/wiki/Open_proxy Like a less sophisticated Tor/VPN that is easily detected by port scans
- galaxy_gas 1y agoMany sites do it .Included in many standard device fingerprinting / anti anonymity SAAS. Ebay facebook etc all do this ! But it looks this is first party to prevent the adblocking of them 1MB of obfuscated fingerprinting + portscan + Webgl . But oddity this one is trying to find burp suite specific route's.
- meitham 1y agoMadness! How do I harden my network against that?
- ale42 1y agoYou should actually harden your browser or PC... to block any unwanted requests. Apparently some browser extensions can do that.
- bawolff 1y agoChrome is already in the process of killing it https://developer.chrome.com/blog/local-network-access https://developer.chrome.com/blog/local-network-access
- ahdanggit 1y agoThe company I work for has a legitimate service that runs on the loopback (it provides our web apps APIs for some device integration) hopefully its just as simple as the user accepting the prompt else we'll be drowning in support. We had to go the path of the local service because they killed NPAPI. I've been thinking about using web serial as an alternative but Firefox doesn't support it. That being said, I think this is an overall win, hopefully Firefox implements it in a consistent manner as well.
- ayewo 1y agoHow is your company's service started on the loopback interface? You bundle a web server that is installed alongside a native app?
- ahdanggit 1y agoRoughly, yes. Customers (or more often, their IT department) runs our installer which installs the server as a windows service.
- galaxy_gas 1y agoThis how many of them work for transporting vs traditional old way of registering url scheme and requiring user interacts --- Discord, Blizzard net, Riot Client ... all localhost listener's that can interact
- dns_snek 1y agoEnable "Block Outsider Intrusion into LAN" filter list in uBlock Origin.
- meitham 1y agoThank you!
- bmacho 1y agoIt would be the job of the operating system to give or take away the ability of your browser to access your local network. But you can run your browser in a container/vm and disable localhost. (And use a separate browser for localhost only if you need it.)
- ahdanggit 1y agomy bank did this on the site they sent me to in order to activate my new card.
- kolla 1y agoMy biggest grief with that site is that it's like something from the 90s.
- bhaney 1y agoAs something from the 90s myself, I find this rude.
- SnuffBox 1y agoIt's also inaccurate, as this style of page (relating to layout and specific graphic style) didn't appear until 2006ish.
- danw1979 1y agoThe 1990s web was actually good
- thrown-0825 1y agoYeah it should have a fixed header and footer along with a pop-up consent drawer so you can only see 10% of the actual site content. So much better. Modern web design is a joke.
- davsti4 1y agot-shirt worthy quote - "modern web design is a joke" ;)
- yard2010 1y agoI think you are confusing something from the 90 with something from the gov
- jansper39 1y agoThese guys need to look at Gov.uk, this site is a total horror show.
- SnuffBox 1y ago
- asimovDev 1y agoEmbarrassed to say that I wasn't aware of this practice. Are there malicious uses for this beyond fingerprinting?
- asimovDev 1y agohttps://files.catbox.moe/g1bejn.png https://files.catbox.moe/g1bejn.png When I visit the site from Safari on macOS I see this in the console. Are there any particular services that use port 8888 for the website to do this?
- jadamson 1y agohttps://my.f5.com/manage/s/article/K000138794 https://my.f5.com/manage/s/article/K000138794 It seems to be part of some "bot defense" product by these F5 people, to "test the different browser capabilities". I doubt it's intended to hit a real endpoint on any system.
- palmfacehn 1y agoRouters with vulnerable URLs. You can search for: "router" "authentication bypass".
- causal 1y agoIsn't CORS supposed to prevent this?
- layer8 1y agoCORS doesn’t prevent requests (i.e. GET requests from IMG tags, or XHR preflight requests), it only prevents web apps from processing the response if the responding server doesn’t agree. And a simple GET or even OPTIONS request can be enough to exploit vulnerabilities in routers and other local devices.
- inferiorhuman 1y agoMostly it's great for tracking although I'm sure it could also be used to exfiltrate data (e.g. if the user is running something sensitive on localhost). https://www.digitalsamba.com/blog/metas-localhost-spyware-how-webrtc-was-abused-and-how-to-stay-safe https://www.digitalsamba.com/blog/metas-localhost-spyware-ho...
- vaylian 1y ago> Blocks malicious websites from port-scanning your computer/network How does that work? A browser extension can't influence how your router and other machines in your network react to incoming requests.
- Mashimo 1y agoJudging just from the screenshots, it seems it blocks websites from accessing 127.0.0.1 get requests. Not a port scan to the outside, more of what do you have running on the local machine inside your network.
- est 1y agobut it can hook javascript methods before that scan can happen.
- ale42 1y agoAs far as I understand it, it is supposed to be a scan done by the browser on the user's computer, not an external scan, which a browser extension wouldn't be able to detect.
- bawolff 1y agoHopefully should soon be a thing of the past with https://developer.chrome.com/blog/local-network-access https://developer.chrome.com/blog/local-network-access
- vaylian 1y agoI see. So the website would try to access private IP adresses (RFC 1918) by having elements like <iframe src="http://10.0.0.1 http://10.0.0.1"> in the web site and then the web site would check if the iframe was loaded successfully?
- Delk 1y agoIt could also just try making the request with javascript. Or try a websocket connection.
- edarchis 1y agoVisa application is riddled with scams. From the simple website that charges you twice the price to websites that will tell you that you were rejected and then fake your documents to get in with your name. So they're probably trying to see that you're not one of those web servers, a proxy for them or detect some known C2 channels.
- jaimehrubiks 1y agoThis is a very clever answer.
- deleted 1y ago[deleted]
- testdelacc1 1y agoAnother data point - 5he Indian visa system is similar. The official website ending in .gov.in, which is hard to find, offers a visa for $10 and minimal hassle. The scam websites, with better SEO sell the same shit for $80. They’re just proxying your application to the real website and pocketing the difference. It would be good if the Indian government could block the scammers but I guess it’s a lower priority for the moment.
- M95D 1y agoI'm using uMatrix and it blocks by default all connections outside the requested site and parent domains. For example, if I request https://mail.yahoo.com https://mail.yahoo.com, connections to yimg.com are blocked. I need to manually allow each CDN for each website, so this attack/profiling won't work. Using uMatrix was very annoying at first, most websites are broken without their CDNs, but after a few months or so, the whitelist grew and it contains 90% of websites I visit. On my system https://ceac.state.gov/genniv/ https://ceac.state.gov/genniv/ tries to connect to captcha.com, google-analytics, googletagmanager, 127.0.0.1 and "burp" (a local hostname that doesn't exist in my network). Interestigly, the browser console doesn't list connection attempts to localhost or burp. If I allow 127.0.0.1 and "tcpdump -i lo", I see connections to port 8888, which isn't open.
- samsonradu 1y agoHow does it manage to hide the requests to 127.0.0.1 from the network tab?
- M95D 1y agoI have no ideea. Possibly that's a limitation of Chrome+Firefox developer tools (I get the feeling it's the same code)? But I found what "burp" is: https://portswigger.net/burp/communitydownload https://portswigger.net/burp/communitydownload
- culturestate 1y agoIt seems like they only make the localhost requests on your first visit. If you open devtools in incognito mode (or just clear the cookies) before accessing https://ceac.state.gov/genniv/ https://ceac.state.gov/genniv/ you should see those 127.0.0.1 attempts as ERR_CONNECTION_REFUSED in the network tab. Somewhat more worryingly, Little Snitch doesn't report them at all, though that might just be because they were already blocked at the browser.
- inferiorhuman 1y agoThis is what I see. https://i.imgur.com/lvjg2YQ.png https://i.imgur.com/lvjg2YQ.png
- trod1234 1y agoCapturing forensic artifacts of the local network allows a building a bridge strategy for identifying fraudulent networks without requiring knowledge of the path taken from destination to recipient. Other local devices do this and send the network map during a phone home, allowing comparison to a source of truth that is tied almost directly to the person, or group of people. There is also a lot of fingerprintable material within such a port scan from clock skew, TCP ISN, and a few other areas. You can sieve this quite easily with this available, thanks to Roku's, Phone's, and other things doing this while just sitting locally in a shared collision domain (a digital soldier quartered in every home). The metadata node graph of devices locally acts as a unique fingerprint once in RFC1918 space, technically not unique but close enough.
- slyall 1y agoBe careful your security tool isn't producing false positives. I remember years back when people would run these firewalls and we'd get complaints from home users about normal traffic. Thinks like complaints our mail servers was scanning them on port 25 when they sent email.
- LoadingXD 1y ago[flagged]
- gethly 1y agoJust a little side note - in this context, it makes sense if the website tries to connect to a local port because you might be running a card reader(ie. terminal). This is how it works with some(all?) EU countries that have a chip in their ID cards, or even vehicle registration cards, which you can use to access sensitive information or perform certain administrative tasks on government websites. Although, from personal experience, it used to require java and it worked only on internet explorer and since it has been retired and replaced with chromium, i am not sure what is the way to make it work nowadays, as i have not been able to figure out to use it when i needed the last time.
- cjrp 1y agoI've had it before where it asked me to use an iPhone/Android app which can read the passport's NFC chip. I guess that's the modern replacement for IE/Java.
- layer8 1y agoIt requires installing a local service that bridges between the browser and the smartcard driver (what Java applets did in earlier years). The web app then communicates with the service via requests on localhost. The card-specific driver and bridge service are often bundled together for installation.
- dns_snek 1y agoThe "port scan" just seems to be a local connection to 127.0.0.1:8888. I don't know what purpose it serves on this page, but our government websites often use this technique to communicate with native software for digitally signing documents. Are you seeing connection attempts to other IPs?
- junon 1y agoMight also be card readers, debug servers, etc. Could also be incompetence :D until I fixed it, deploying from my local machine rather than CD resulted in one of the baked in URLs being localhost rather than the public host on the project I'm working on now. Their local development server might just be at port 8888. Wouldn't surprise me.
- dns_snek 1y agoI looked at the website again and noticed that the request paths looked odd, one of them being `/400_random_url_with_numbers_403`. I googled that and it looks like it's part of a client-side bot detection script that's testing something, the explanation isn't very informative. https://my.f5.com/manage/s/article/K000138794 https://my.f5.com/manage/s/article/K000138794 > These requests are caused by the bot profile to test the different browser capabilities. > 'http://127.0.0.1:xxxx http://127.0.0.1:xxxx' request is a call to the localhost/client machine, which is normal when trying to protect assets like end-server using ant-bot defense. It does not have any impact regarding application page load.
- tifkap 1y agoThis is most likely an attempt to connect to a webserver on your own device to collect data and/or do tracking. Remember back in June when Facebook/meta got caught tracking users trough a webserver on Android phone thought Messenger and Instagram? Same thing. See: https://news.ycombinator.com/item?id=44169115 https://news.ycombinator.com/item?id=44169115 and https://news.ycombinator.com/item?id=44175940 https://news.ycombinator.com/item?id=44175940
- darkwater 1y ago
- tmdetect 1y agoVery interesting. Having looked at NoScript it seems like you can disable LAN as a default value under the allow tab.
- tmdetect 1y agoLooking further * uBlock Origin and Lite have it as an option under Filter List > Privacy > Block Outsider Intrusion into LAN * Brave prevents it, tested with Aggressively block Trackers and Ads.
- codedokode 1y agoWhy do you need a heavyweight extension to block sites from scanning your local network? Ridiculous. Also I wonder if this protection is available only with old extension manifest version or new network request hooks API also supports it.
- karel-3d 1y agoIt's coming from a F5 script, which is a company that sells anti-bot protection amid other things. (It's coming from obfuscated script at /TSPD, which is a F5 thing.) https://www.f5.com/ https://www.f5.com/
- karel-3d 1y agoTS seems to be short for TrafficShield (a product of some company F5 acquired in early 2000s) and PD seems to be Proactive Defense (?)
- jpeggtulsa 1y agoIsn't F5 the company that makes nginx?
- vkardco 1y agothis is awesome
- reneberlin 1y ago[flagged]
- jas- 1y ago[dead]
- lordofgibbons 1y agoHow and why do browsers allow this? Why wouldn't the browser ask for permission in the same way that it does for Microphone access? It's insane to allow any random website to port scan my LAN. If this wasn't a "feature", I would have considered this a high severity vulnerability
- deleted 1y ago[deleted]
- JJJollyjim 1y agoChrome doesn't allow it - local network services have to opt-in to being fetchable from public sites (https://github.com/WICG/private-network-access https://github.com/WICG/private-network-access), although they're replacing it with a user-permission-based approach (https://github.com/WICG/local-network-access https://github.com/WICG/local-network-access). (There is some language online suggesting PNA has not actually shipped, but I experienced it myself in stable Chrome several years ago, so I am unsure of the current state). Firefox doesn't implement either approach -- I assume this is indicative of their lack of development resources.
- adithyassekhar 1y ago> Firefox doesn't implement either approach -- I assume this is indicative of their lack of development resources. Since ublock had this as a feature for a long time, I'm sure they are aware of it. Unlike other non funded oss projects, Firefox can't and shouldn't shield themselves with this lack of development resource excuse. They have millions.
- johncolanduoni 1y agoA trillion dollar company (that loves huge vanity projects) gave up on maintaining a browser because it was too much work and just ship a Chrome fork now. I won’t defend Mozilla’s allocation of their resources, but even if they put it all into the “right” Firefox features the web platform is too complex and too much of a moving target for a company with mere centi-million revenues.
- b3lvedere 1y ago"Since looking into it, I noticed that uBlock Origin already has the default list "Block Outsider Intrusion into LAN" but it wasn't enabled." Never knew that this existed. Thank you!
- dd_xplore 1y agoIs that available in lite version too? Now that the origin js being phased out
- nicce 1y agoYou can't change browser? Or is there something bigger happening?
- surajrmal 1y agoNot everyone wants to change browsers.
- LarMachinarum 1y agothen again, if the makers of one big browser (and via there also the derived browsers) start force-shoving spyware upon you (by restricting blockers), it comes down to a decision of how you set your priorities. Personally, It's a clear cut red line, but you do you.
- daveidol 1y agoIt’s only being phased out on Chrome, by Google.
- ddlsmurf 1y agoYes, to make us safer, now you enable developer mode and disable signature checking to install it locally, thanks Google
- 1y ago
- e40 1y agoThat extension has "Access your data for all websites" ... I really don't get how anyone can give that permission to anyone that isn't well known (a company with a lot on the line) or a person famous for their work (the uBO dev) who has stated he will never sell to anyone or do bad things. "Hacks and Hops" doesn't even have a valid home page. The extension links to https://g666gle.me/ https://g666gle.me/ which does not exist. The domain name itself does not want to make me give access to all my data for all websites to them. As nice as this extension seems, I would ever in a million years install it.
- jeffbee 1y agoUnfortunately this level of incoherence is almost universal on HN and similar forums. You'd have to be completely out of your mind to install this extension, but people for some reason believe they can install privacy. They got whipped into fearing nebulous online actors so much that they'll download FSB rootkits dressed as VPNs. The minimal set of actions a rational person would take after realizing they've been tricked into installing this extension is setting their entire PC on fire and then running it over with their car, while moving all of their bank accounts to new accounts, in person, and changing all of their passwords using a brand new device.
- jmclnx 1y agoIf would be interesting to see what happens on OpenBSD. With pledge(2) and unveil(2) in Firefox, I wonder what it would see. I expect it would see nothing. I will give it a try and see what happens and if I see anything I will add it here.
- jmclnx 1y agoI saw nothing of note on OpenBSD. I added the plugin and it prompted me an attempt was made to scan the network, it said it blocked the scan SO, I guess that is going to be used on all my firefox runs.
- uticus 1y agoPushing the burden of network permissions management outside the browser, to the OS? Heresy! To be serious, this has introduced me to sandboxing on BSD via pledge [0] and comparisons against Linux seccomp [1] - thank you! [0] https://news.ycombinator.com/item?id=17289654 https://news.ycombinator.com/item?id=17289654 [1] https://kristaps.bsd.lv/devsecflops/ https://kristaps.bsd.lv/devsecflops/ (submission by same poster at https://news.ycombinator.com/item?id=44264021 https://news.ycombinator.com/item?id=44264021)
- jhoechtl 1y agoChecking if you are sharing torrents, run a tor node, mine coins?
- 77pt77 1y agoIt's most likely smartcard authentication code.
- trollbridge 1y agoFor another example, studentaid.gov doesn’t work in private browsing.
- jeffbee 1y agoIsn't it sort of contradictory to try to use private browsing with a service that requires your identity?
- kccqzy 1y agoNot contradictory at all. These days private browsing for most people just means (1) don't save the browsing history and (2) log me out of all websites temporarily.
- jeffbee 1y agoBut as the other post notes, it goes further (than, for example, Chrome Incognito) in ways that can break sites. Incognito means exactly what you said, while Safari Private Browsing means more.
- Sohcahtoa82 1y agoNot necessarily. I might create a login for a porn site so that I can have some favorite videos bookmarked and it can figure out the type of material I like. That doesn't mean I want my history saved locally.
- davsti4 1y agoI just tried opening it in a private window and the page loaded and rendered. What part doesn't work?
- jimt1234 1y agoI can one better (worse): A state-run website that my sister frequents for her job requires Internet Explorer. Seriously. I installed a Chrome extension that modifies her user-agent header to IE, and it works fine. Easy work-around, but totally lame.
- AtNightWeCode 1y agoMost likely some "antivirus" bs. Probably harmless. Fun fact. Most browsers allow by default GET access to web resources on localhost and LAN. Been used for exploits since last century.
- blablabla123 1y agoHave you double-checked whether the IP isn't shared among multiple website domains? That's quite a classic with IP based filtering with hosters like GCP...
- tzury 1y agoData my friend, data. Ports scanning? Well, tell us about the hosts and the port numbers. Add some logs if you got. If you did not go into the details, chances are that when you will, this will turned out to be a false positive case. If you did, where are the evidence?
- deleted 1y ago[deleted]
- gepeto42 1y agoThey’d likely block you if they detected something like RDP open, cause that would likely indicate you’re hiding your real IP address.
- Wowhappyfun 1y ago[flagged]
- soursopfarm 1y ago[dead]