Differences

This shows you the differences between two versions of the page.

--- secure_browsing [2019/08/04 17:12] – neil
+++ secure_browsing [2021/07/06 09:26] (current) – external edit 127.0.0.1
@@ Line 2: / Line 2: @@
 ====Key points: ====
+  *[[#Use a VPN or Tor|Use a VPN or Tor]]
   *[[#Beware of "lookalike" domain names|Beware of "lookalike" domain names]]
   *[[#Use a trusted DNS server| Use a trusted DNS server]] (e.g. by using a VPN, or DNS-over-https, or Tor)
   *[[#Check for a padlock, but it doesn't mean you're connecting to the right site |Check for a padlock, but it doesn't mean you're connecting to the right site ]]
-  *
+  *[[#Use two-factor authentication wherever you can|Use two-factor authentication wherever you can]]
+  * [[#Use "private browsing mode", but be aware of its limitations|Use "private browsing mode", but be aware of its limitations]] — use Tor Browser if you want more protection
+  * [[#Block ads and trackers|Block ads and trackers]]
+  * [[#Block third-party cookies|Block third party cookies]]
+  * [[#Block unnecessary JavaScript|Block unnecessary JavaScript]]
+====Use a VPN or Tor====
+Unless you trust the network to which you are connecting (e.g. your home or office Wi-Fi) and the Internet service provider which provides that Internet connection, connect to a [[virtual_private_networks|VPN]] before you open your browser.
+If you do not have a VPN, use [[tor|Tor]].
 ====Beware of "lookalike" domain names ====
@@ Line 17: / Line 28: @@
 (In this case, Google controls both g00gle.com and google-email.com — probably for the very reason of trying to lessen the risk to users.)
-But these all rely fooling you with a similar, but not correct, URL and, with some additional scrutiny and care, you should be able to keep yourself safe from these type of attacks.
+But these all rely on fooling you with a similar, but not correct, URL and, with some additional scrutiny and care, you should be able to keep yourself safe from these type of attacks.
 ====Use a trusted DNS server====
@@ Line 25: / Line 37: @@
 That's because:
-  * the system which handles the conversion of domain names to IP addresses — the domain name system — is fundamentally insecure. While some sites have adopted techniques to mitigate this, you are unlikely to know which sites have done this.
+  * the Internet's equivalent of a phone book, which handles the conversion of domain names to IP addresses — the domain name system — is fundamentally insecure. While some sites have adopted techniques to mitigate this, you are unlikely to know which sites have done this.
-  * networks often try to be helpful and offer you a DNS service — but the outcome is that you are using the Internet equivalent of their own personal phone book, and you have no idea if they've replaced some of the phone numbers with fake ones.
+  * networks often try to be helpful and offer you a DNS service, but the outcome is that you are using the Internet equivalent of their own personal phone book, and you have no idea if they've replaced some of the phone numbers with fake ones.
 The net result is that you could type the right URL into your browser, but still be directed to a fake site.
@@ Line 33: / Line 45: @@
 To mitigate this, you can:
-  * use a [[virtual_private_network|VPN]], as long as you make sure that your DNS look-ups go over the VPN tunnel. In doing this, you will be using your own choice of DNS server, rather than the DNS server offered by the network you are connected to.
+  * use a [[virtual_private_networks|VPN]], as long as you make sure that your DNS look-ups go over the VPN tunnel. In doing this, you will be using your own choice of DNS server, rather than the DNS server offered by the network you are connected to.
   * use DNS-over-https if your browser supports it. This only protects the browsing you do using that browser.
   * use [[tor|Tor]].
@@ Line 39: / Line 51: @@
 ====Check for a padlock, but it doesn't mean you're connecting to the right site ====
-I’m going to talk about https and encryption in a couple of minutes,
+Before you send anything sensitive to a website (such as login credentials, or anything personal or confidential), check that there is a padlock symbol in your browser's URL bar.
-Now, hopefully, it would be pretty tricky for me to show a padlock for this, but some of the companies which issue the certificates used for security have not got it right every time.
-There are a couple of things I could do.
+{{::screenshot_2019-08-04_at_18.17.58.png|}}
-One would be to generate a self-signed certificate, and hope that you agree to accept it. But that is a bit of a giveaway.
+If you see a padlock, it means that the connection between your browser and the web server is encrypted. Although people spying on your traffic can tell you are connecting to that website, and can tell the volume of data you are sending, they cannot see the content of those data.
-Second, I could try to persuade you to accept a file onto your computer which would trust all certificates which I sign. [How easy is it to do this]
+The padlock only means that the connection is encrypted. It is not a guarantee that the site is the right site, rather than one being operated by a fraudster. However, it makes this relatively unlikely.
-If I manage to do this, then you see the right URL in your address bar, and you see a padlock so you think “oh, good, the connection is encrypted”, but you are still sending your data to me, rather than to your intended destination. And if you put in your username and password, you are sending them to me, enabling me to then log in to your account, and pretend to be you.
+It is also no guarantee that the recipients of your data will not abuse it.
-To protect against this type of attack, you might consider something called two-factor authentication:. I’ll talk about this in the recording about passwords but the gist is that, as well as sending a username and password, both of which are things which you know, you are also sending a one-time token, only valid for that one login, which is generated by something which you have — it could be a phone, or a specific hardware device.
+As a rule of thumb, be very wary giving personal data to a site which is not showing a padlock. But don’t rely on a padlock as a sign that everything is fine.
-It would not stop the rogue site from getting your username and password but it should make it harder, if not impossible, for them to log in pretending to be you, as they would not have the ability to generate that one time token.
+====Think carefully before accepting untrusted certificates ====
+Sometimes, when you are browsing, you will see messages in your browser warning you of a security risk, that the site to which you are connecting is presenting an untrusted security certificate.
+{{::screenshot_2019-08-23_at_16.35.51.png?400|Security certificate error}}
-====Https====
+If you are connecting to a new piece of network hardware which you have just installed (such as a new router, or network-connected storage device) or new server software, and you are confident that the URL or IP address you have typed into your browser is correct, accepting the risk and proceeding should be fine. Even though there is a mismatch between the details in the certificate and the address to which you are connecting, your connection with the server will still be encrypted.
-I have already mentioned https — the secure version of hypertext transfer protocol, which is the series of messages for the transfer of data to and from a web server.
-Generally told to look for the padlock.
+If, however, you are just browsing and you stumble across an error like this, it is safest if you browse away from the site in question, without accepting the certificate. You might be fine, but it may also be an indication that someone is trying to intercept your browsing, or is trying to trick you into visiting a fraudulent copy of a site.
-Unfortunately, what the padlock means, and what trust should be placed on the site as a result, has not always been communicated well.
+====Use two-factor authentication wherever you can ====
-The padlock means just one thing: that the connection between your computer and the receiving web server is encrypted
+In addition to a username and a password, some sites will let you also set an additional authentication factor, such as a time-limited code or a small hardware device, which you have to enter before you can log in. This is very common for banks, and is increasingly common for other service providers.
-Nothing more. Not that the operator is who you think they are, or that, even if they are, they are not doing something unwanted with your data.
+It would not stop a rogue site from getting your username and password but it should make it harder, if not impossible, for them to log in pretending to be you, as they would not have the ability to generate that unique time-sensitive code or possess the right hardware.
-You may be sending data to a completely untrustworthy third party, pretending to be someone that you known. You might be sending your data to them securely because of the padlock, but still to the wrong person.
-“secure” v “trusted”. No padlock, not encrypted.
-As a general rule of thumb, be very wary giving personal data to a site which is not showing a padlock. But don’t rely on a padlock as a sign that everything is fine.
+More information on [[two-factor_authentication|two-factor authentication]].
-Check that the URL is what you are expecting.
-Not good if you cannot see a padlock — but seeing one doesn’t mean that everything is fine.
+====Use "private browsing mode", but be aware of its limitations ====
-Encrypts the communication between your browser and the server. Without it, anyone observing your traffic could see not only the other party to your communication, but what you are sending to them — for example, the content of forms, and the pages on the site.
+There’s a strong chance that your browser offers a “private browsing” mode.
-Encryption does not make you invisible: DNS provider can still see your DNS lookups, and ISP can still see where you are going online. But not the pages which you are visiting, or the content of your transmissions, such as form contents.
+{{::screenshot_2019-08-23_at_16.43.02.png?400|}}
-So if you are sending your credit card details online, and don’t want them to be available to anyone observing your traffic, make sure you use an encrypted connection — but make sure you have verified that the site in question is what you are expecting.
+This was commonly discussed as a mode which you were supposed to use when buying a present for a loved one, so that they would not find traces of your secretive gift habits if they happened to use your computer. In reality, it’s pretty much universally known as “porn mode”, for much the same reason.
-Some degree of checking that the certificate has been issued to the right site?
+If you do not want your //browser// to retain a record of what sites you have visited, private browsing mode is reasonable way of doing this — it saves you having to clear your history, cookies, cache etc manually.
-====Cross-site and repeat-visit tracking====
+Private browsing does not stop:
+  * the sites you visit from logging information about you, such as your IP address.
+  * your network provider from seeing (and potentially recording) your traffic.
-Loading images from remote servers
+So it can be a useful tool if you do not want your computer to retain information about your browsing, but be aware that it does not hide your browsing from your Internet provider.
-Every time you connect to a site, you are sending information to it — your IP address, and some information about your browser configuration.
+If you want to do that, then [[tor|Tor]], especially via [[https://www.torproject.org/download/|Tor Browser]], is a better option.
-Where a page hosts images from multiple other sites, you are sending your information to all of those sites.
-So every time you load a page containing a Facebook element, your computer is talking to Facebook. Easy to build up a picture of your activity over time.
+====Block ads and trackers====
-Imagine every time you go into a shop, or visit a friend, or read a news story, you are ringing someone and saying “hi! I’m over here now!”. That is basically what is happening.
+Many websites, and other third parties, will use different techniques to try and track you. This is mostly for the purpose of trying to learn more about you, in an attempt to show you what they think are relevant adverts.
-Technically, it does not matter if you are logged in or not — but staying logged in to Facebook, Twitter, LinkedIn etc can only help matters.
+Blocking adverts and trackers can cut down on this spying, and may also have the beneficial side effect of making web pages load faster.
-====Clearing your cookies and cache====
+There are various techniques for blocking these things:
-Sites may store information on your computer, in the form of cookies.
+  * [[https://pi-hole.net|Pi-hole]] is a piece of software which you run on a computer on your network (it is named after the cheap, low-powered computer, the [[https://raspberrypi.org|Raspberry Pi]], which is excellent for this type of thing). You configure it so that all computers on your network (including computers, phones, and "smart" devices, such as TVs) use it as their chosen DNS server. It regularly checks online lists of known ad or tracking servers, and gives DNS look-ups for those sites a fake answer, so that you do not load them.
+    * As a bonus, if you use a VPN to connect back to your network, you can use your Pi-hole system to block adds on your computer or mobile device, wherever you are connecting from.
+  * on-device software, usually in the form of a browser plug-in, such as [[https://github.com/gorhill/uBlock#installation|uBlock Origin]] and [[https://www.ghostery.com|Ghostery]].
-You can delete these (or refuse to receive them in the first place) through your browser settings.
-Blocking all cookies might make some sites work poorly — if a cookie is used for keeping your login session active, for example, or maintaining the content of your shopping basket before you check out, disability cookies could result in a really poor user experience or failed transactions.
+====Block third-party cookies====
+Sites may store information on your computer, in the form of small text files known as cookies. They may also use other techniques, such as running bits of code in your browser.
-Removing cookies will limit the information that a site can collect on you, but will mean you need to keep logging in.
+You can delete these (or refuse to receive them in the first place) through your browser settings.
-===“Supercookies”===
+Blocking all cookies might make some sites work poorly — if a cookie is used for keeping your login session active, for example, or maintaining the content of your shopping basket before you check out, disabling cookies could result in a poor user experience or failed transactions.
-Information injected into your browsing by your ISP. VPN may assist — assuming that your VPN provider is not modifying your traffic too…
-===Tracking without cookies===
+Blocking third party cookies, or enabling the option to prevent cross-site tracking, is unlikely to pose any usability problems, while increasing your privacy.
-Even without cookies, still possible to track you:
-Combination of IP address and browser-specific information.
+For example, in Safari on macOS, it is in Settings / Privacy, and it looks like this:
-EFF’s “panopticlick” tool: https://panopticlick.eff.org
-Looks at the variety of information available from your browser, and suggests how many other browsers will look indistinguishable from yours. When I tested my browser, it showed it would be pretty easy to identify it: 1 in 100,000 browsers.
+{{::screenshot_2019-08-04_at_19.20.14.png|}}
-===Blocking ads===
-A slightly controversial topic is that of blocking ads.
-This entails running software either on your phone or laptop, or else on the network itself, which attempts to detect requests your devices make for adverts embedded in webpages, and blocking them. The software to do this is readily and freely available.
+===Tracking without cookie is still possible===
+Even without cookies, it may still be possible for a website to single you out, using a combination of IP address and browser-specific information.
-The reason I say it is controversial is that, for all its sins, online advertising, especially targeted advertising, funds as lot of sites, and blocking ads may have an adverse impact of their viability. That’s increasingly why, if you have an ad blocker running, you see “ad walls” pop up on the page you are trying to visit, telling you to drop you ad blocker or else leave.
+You can see how unique you are using the EFF’s [[https://panopticlick.eff.org|“panopticlick” tool]].
-For me, that’s probably a good enough sign to leave, but others may feel differently.
+====Block unnecessary JavaScript====
-Generally, irritating though they are, particularly when they block the flow of text on a page, it is not the advertisements themselves which are objectionable.
+In addition to blocking ads and trackers, and blocking third party cookies, lots of websites use JavaScript. This can be for legitimate reasons such as improving the user interface, but they may also be malicious (such as using your computer's power to mine cryptocurrency) or else a vehicle for obtaining information.
-More usually, it is the fact that the advertisements are targeted. And, to achieve this, data about the sites you are visiting, and about your computer and software, and sent to third parties who run advertising networks, to enable them to try to shove you the advert which they think will get the best reaction from you.
+Switching off JavaScript is unlikely to be tenable, as it breaks core functionality of many sites, but there is no harm in trying it and seeing how you get on.
-You might be surprised just how many people are tracking you on your favourite websites — tools such as Ad Block Plus and Ghostery, which you add in to your browser, can help you see just how much is going on.
+If you find you cannot switch of JavaScript completely, tools such as [[https://noscript.net|NoScript]] are browser plug-ins which let you control what scripts get run.
-Unfortunately, there is no common way of accepting the advertising without the tracking, so your option is pretty much accept both or block both.