November 30th, 2017

Cyber Defense Skill: URL Reading

Want to quickly sort out real emails from spam? Spot a bad links on web pages? Identify sham web sites? I have a suggestion: learn to read URLs.

Learning to read URLs is like taking a class in street self-defense or carrying a can of mace. Actually, much better because reading URLs can’t be turned against you. You might end up in the hospital or worse if you resist a street thug with your self-defense skills, but you will never be injured spotting a bad URL.

Uniform Resource Locators (URLs), more properly called Uniform Resource Identifiers (URIs), direct all the traffic on the World Wide Web. Almost every cyber-attack directs traffic to or from an illegitimate URL at some point in the assault. If you can distinguish a good address from a bad address and develop the habit of examining internet addresses, you will be orders of magnitude more difficult to hack.

Addresses are constructed according to simple rules. You can master the rules you need to know in order to distinguish legitimate addresses from scams in a few minutes. And be much safer.

If you want to dig deep into URLs, take a look at RFC 3986. There is much more to URLs than I cover here.

Here is a typical simple URL:


The first part, called the scheme, “http:” tells you that it is a HyperText Transfer Protocol (HTTP) address. You need to know two things about the HTTP scheme. First, almost all data on the web travels to and from your desktop, laptop, tablet, or phone over HTTP. In fact, if an address does not begin with “http”, it’s not a web address. There other schemes, the most important of these is “mailto:”, which designates an email address. More on this below.

Secure HTTP

There is an important variant of HTTP called HTTPS. The “S” stands for “secure.” Data shipped via HTTPS is encrypted and the source and destination are verified with a security organization. HTTPS used to be reserved for financial transactions, but now, with all the dangers of the network, HTTPS is encouraged for all traffic. When you see “https” in a web address, hackers have a hard time snooping on your data or faking a web site. HTTPS is especially important if you are on open public WiFi at a coffee shop or other public place.

Not too long ago, security experts said HTTPS guaranteed that a site was legitimate. That is no longer good advice. HTTPS is not a guarantee that a site is legit. Smart scamming hackers can set up fake sites with HTTPS security. You have to check the rest of the address for signs of bogosity. However, setting up a fake site with a legitimate address is still hard, so a good address with HTTPS is still a strong bet.

HTTP address “authority”

The part of the address following the “//” is the “authority.” Most of the time, the authority is a registered domain name. The authority section of a URL ends with a “/”. Notice that the slash leans forward, not backward. A backward slash is completely different. The “query” follows the forward slash. The query usually contains search criteria that narrow down the data you want retrieved and is often hard to interpret without specific information about the domain. You can ignore it, although sometimes hackers can learn secrets about a web site from information inadvertently placed in the query.

Domain extensions

In the above address, “” is a domain name that I have registered with the with the Internet Assigned Number Authority (IANA). “.com” is the extension. In the old days, there were only a few extensions allowed: “.gov”, “.edu”, “.net”, “.com”, and “.mil”. They are still the most common, although many others— such as “.tv”, “.partners”, “.rocks” and country abbreviations— have been added.

You can use extensions as a clue. For instance, most established firms and organizations still use the old standbys. A web site with a “” domain is likely not the American Express you think it is. We all know that some countries harbor more hackers than others. If an address has an extension that is an abbreviation for a cyber rogue state, be careful.

Remember, these are clues, not rules. A street lined with wrecked cars and broken windows may be crime free, but more often than not, it is a dangerous neighborhood. The same applies to incongruous domain names. They could be safe, but there is a good chance they are not.

Authority subsections

The authority section is divided by periods (“.”s) and reads in reverse. The extension that immediately precedes the first forward slash is the most important. “.com” in “” indicates that the domain is in the vast segment of the internet made up of commercial ventures. “marvinwaschke” determines which commercial venture the address refers to. “www” indicates that the address points to the “www” part of the “marvinwaschke” venture. I could set up my website to have a “” section or a “” section if I cared to. The “www” is historically so common, most browsers will strip it off or add it on as needed to make a connection.

“” only indicates that my web site has a section devoted to Microsoft. “” has nothing to do with Microsoft Corporation. Hackers make use of this to try to fool you that “” is a Microsoft site. It’s not! Hackers are creative. Make sure that the right end of the domain name makes sense.

Email URIs

Email addresses are URIs that follow a different scheme but use the same domain name rules. Usually, email addresses drop the “mailto” scheme but they can always be fully written out like mailto:// If you see an address like you can be fairly certain that the mail did not come from Bill Gates.

When in doubt, Google it

When you see a link or address with a suspicious domain name, Google the domain name before you use the address. Most of the time, Google will pick up information on dangerous domains.

Look at every link with caution

The internet is all about grabbing your attention. Absurd promises abound that that few people would take seriously after they took a moment to think. Losing weight is hard, wealth management is useless if you aren’t already accumulating wealth the hard way, and no miracle food will prevent cancer or make you a genius. Not all ads are scams, but  don’t tempt fate by clicking on links that prey on impossible hopes.


Make a habit of looking at internet addresses. If you place the cursor over a link or address, most browsers and email tools will display the working address. Look at the address. Does something look wrong? If so, use care. The habit of looking at addresses will make you much harder to hack than unsavvy computer users.

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