Why are there websites in my browser history that I’ve never been to?

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I periodically clean my browser history, but after a while website entries begin to appear in it that I’ve never actually been to. Some of these sites look quite disturbing, and are not sites that I would ever go to. Why would these entries appear? Do I have spyware or a virus?

This is a question I get relatively often, and it’s usually nothing to worry about.

Certainly viruses or spyware are a possibility. Of late I’d also call out “Foistware” – the software that often appears on your system unexpectedly after installing something else.

However there are also more benign scenarios. It’s possible your browser may simply be doing a good job protecting you.

Spyware and Foistware

Spyware often works by forcing your browser to go to places you would never go. Foistware in particular often adds toolbars and other software to your system that intercepts what you’re doing and just rudely takes over, sending you to bogus search sites or worse.

These days my first recommendation when you run into unexpected history entries is to make sure your machine has no unexpected malware. In particular I’d have you run the tools outlined in How do I remove PUPs, foistware, drive-bys, toolbars, and other annoying things I never wanted?

Traditional pop-ups

Many websites employ pop ups – additional browser windows that open up when you visit the site. These typically contain ads for which the site owner is  getting paid.

HistoryPop up blockers were created to prevent pop up windows from happening. Using different techniques, the blockers intercept the requests to create new browser windows and prevent them. Most modern browsers include pop up blocking technology of some sort.

Pop up blockers insert themselves into the normal processing of web requests, and “kick in” when they detect that a pop up window is being requested. Exactly where depends on the specific blocker and how it operates. It actually gets fairly complicated, since there are so many different ways to create a pop up window. That’s why some blockers are more effective than others.

My theory is simply this: a URL that’s been requested to open in a pop up window may actually get added to your history before the pop up blocker kills it. You’ve never seen it, but it’s there in the list.

One page, multiple sources

History entries certainly don’t have to be created by pop ups alone.

Some pages on the web that look like a single page are, in fact, a composite of more than one page or page fragment. What you see as being a single URL may in fact, have fetched content from several different sites.

Depending on how your browser handles these requests, it’s possible that these sub-pages or page elements could also show up as individual entries in your history. You wouldn’t recognize them, because they’re not pages that you explicitly went to, but they’re present because they were part of some page that you did visit.

Ultimately, unless someone else is using your computer when you’re not looking, I believe that this is typically a very benign occurrence.

However that shouldn’t stop you from taking the appropriate precautions to keep your computer safe.

This is an update to an article originally posted : April 17, 2006

There are 16 comments:

  1. Randy Reply

    There’s one major possibility you didn’t address, Leo: just because he doesn’t go to “those” kinds of sites doesn’t mean other’s don’t, if others use his computer. Indeed, does he have teens in the house? They could be doing things and going places on his computer that he wouldn’t approve of….

  2. Marvin Reply

    After searching for an hour online I finally found this clear explanation of why stuff is appearing in my history when I have never been to these sites. Most of them are porn! I’m glad my pop up blocker is working and I’m not going crazy! Every site online is telling me I’m looking at this stuff when I’m not!

  3. Martin Reply

    thank you i think its the poker pop ups that are doing this because i click on allmost everything that comes up
    thanks

  4. Tiffany Reply

    A similar thing has happend to me..I found a bunch of stuff in my web history that I didn’t go to. They were all from the same site and in 2 different web history that I have. Porn of course..is this still possible that it is spyware?

  5. banefulpurity Reply

    So my husband goes on websites like flikr and too shocking and I have found some stuff in the History – but it’s hard for me to get mad when i’m unsure if he’s actually going on these sites.
    How can i tell? is there a tool for this?

    • Tom Dees Reply

      You should stop going to that website …..I would simply block it. I have helped several friends clean their machine after visiting that particular site.

  6. Samantha Dolton Reply

    This happens quite often to my families cpu also. The culprit in our case is angieslist and craigslist!!!ugh

  7. BillV Reply

    I’ve observed the converse, i.e. that some sites that I’ve been to don’t get added to the history. The includes some Ebay pages but the really obvious one is Google. At one time the pages associated with all my Google searches were added to the history. This doesn’t happen any more. Is there an option that I don’t know about that has been switched?

  8. tamzin lewis Reply

    so in my partners phone browser history was a mobidateing…..more than once apparantly browser history rekons the site was visited there was no difference between that link and the other sites he visited ie, colour and of course he denies this and im currently pregnant and find this very upsetting can anyone help and shed some light on this please!!

  9. Sanjoy Kr Bandyopadhyay Reply

    Browser history shows the sites visited from other PC & other person. What the reason may be?

    • Connie Delaney Reply

      If you are signed into Chrome on those various computers it will sync the browsing and history. And also a good lesson that if you are asking a question about a computer it’s essential to include some information about the system and programs you are using.

  10. joyann Reply

    So my husbands computer history keeps showing that he is visiting some girls page on Facebook. He’s not friends with her on his page and says he doesn’t know her. He denys it adamantly and I want be believe him, but something just doesn’t add up. A guy he knows that works on computers said it could be a bot. What do you suggest?

    • Leo Reply

      All I can say is that there are ways it can happen without his having done it.

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