3

Say someone had got hold of my public IP address, what can they do with it? It is a public IP address though. What can someone do with it?

Tetsujin
  • 49,589
hmood
  • 37

1 Answers1

8

Your public IP Address is known by every single internet connection you ever make; that's how they know who to send a web page or a file or a video to.
As most consumer IP Addresses are dynamic, you may in fact not have the same address tomorrow, if your ISP assigns a new one out of their available pool, or you may have the same one for 10 years.

If a human gets hold of your IP Address, they can do a geographic lookup; this, depending on where you live & your ISPs distribution network could place you to within maybe 5 or 10 miles. Mine places me about 5 miles from where I actually live - a circle which covers a population of perhaps a million people.
An edge case - if your address never changes, then sites can use it to track your habits… but a lot of them do that anyway, using cookies or more nefarious tracking methods.
Ever wondered why you can look at a product online then 10 minutes later see an advert for it on Facebook?

There is the remote possibility that someone could do a port scan to try to find weaknesses in your router, but hackers have bots doing that all day every day anyway. The chances of you being singled out for special attention are likely dependent on whether you routinely troll 'script kiddies'* on dodgy sites, or might be of particular interest to a government body.

*Script kiddies - usually younger users, learned one attack vector from their script kiddie chums, then use it to attack people for 'fun'.

Tetsujin
  • 49,589
  • 1
    There's also the possibility to attempt connections to open ports, but 1) if you have a router/modem, that would be router's/modem's ports unless you're in DMZ; 2) bots are doing it anyway for random IPs, so knowing that a particular one is yours doesn't to much. – gronostaj Sep 15 '20 at 08:33
  • @gronostaj - I'd thought of that one earlier but didn't put it in because of the likelihood of it happening to one specific person. Added now. – Tetsujin Sep 15 '20 at 08:56
  • 2
    They could also DDOS your IP, effectively saturating your connection. It may not do any damage, but it could make your internet unreliable and effectively useless for a period of time. They may not get past the firewall, but the internet pipe will be full of useless data. This is not typically viable as a real "attack" as a router reboot will get you a new IP, but it could be used as a method to drop people out of online games for an easy win. Many systems may centralise servers or connections to prevent this kind of abuse. – Mokubai Sep 15 '20 at 09:28
  • Just to add, my brother made someone mad on an online game. They somehow got our IP address from the game (or through some other means like tricking him into clicking a link), and DOS'd us for a couple days. We ended up just shutting down our router until we could get a new address because we couldn't use the internet anyways. – Carcigenicate Sep 15 '20 at 17:35