Late last week I read about a particular form of adware that Google is continuing to work to prevent it from interfering with search engine results or obscuring your view of a popular website.
These ad injectors display pop up dialog boxes on your screen obscuring the website that you wish to view and instead offer tech support scams. They can also place ads that they wish to promote over the genuine search results that you have just requested from Google (or another search engine). For more signs/symptoms to look for, this blog post provides more details.
These ad injectors come to be installed on your computer from browser extensions/plugins as well as more traditional advertising toolbars.
In order to remove and prevent such ad injectors from disrupting your browsing experience I would recommend running a quick scan with your preferred anti-malware software (run a full scan if anything is detected). If you are still seeing annoying pop up dialogs or unwanted ads (that overlay the genuine search engine results) you could also try a free scan with one or all of the tools mentioned below (that I also mentioned on my Tools and Resources page).
In addition, before installing any free browser extension, check/read the reviews of it before downloading it and research it online a little before installing it. If you begin to see unwanted ads just after installing a new browser extension, uninstall that extension. To be even more careful, consider running the scans that I mention above after installing the extension just to ensure the legitimacy of what you have just downloaded.
Please consider supporting the future development of these free scanning tools by donating via their websites (especially if they find and remove any adware for you):
Junkware Removal Tool:
Note: For the Junkware Removal Tool, I would recommend backing up your data to another external destination (e.g. an external hard drive or offsite backup, don’t have the backup accessible on your computer when running the tool) before running this tool. This is because it can delete any application installer that includes advertising toolbars as part of its installation (even if such toolbars are optional). You may not be expecting such installers e.g. Oracle Java to be deleted (without any prompts) and having a backup reduces the inconvenience of such application installers being deleted.
Update: 6th May 2015:
Since this post was originally posted Google have since provided more details on their findings from a research study detailing the extent of the ad injector ecosystem.
Google have worked to remove extensions from the Chrome Web Store that were deceptive and their Safe Browsing API continues to protect users from downloading software that is not what it appears to be. In addition changes to their AdWords policies have seen the number of Safe Browsing warnings being presented to users drop by 95% (i.e. users are no longer being manipulated into attempting to download dubious software/ad injectors and thus the warnings are not necessary).
The advice that I provided above still remains valid; however Google have since released a software removal tool to remove existing ad injector software. If you suspect that you may have such an ad injector installed, please consider running this tool. I have used this tool and it’s scan takes less than five seconds to complete (for me the scan showed no malicious results and thus no action was required).
Update: 25th September 2015:
Earlier in September Google mentioned that they have made adjustments to their online advertising system so that ads that appear as a result of the ad injectors mentioned in this post are no longer bid on and thus no revenue is generated.
Google acknowledges that this measure won’t stop all of these ads from appearing but it makes it much less profitable for those who create these unwanted ads.
I hope that the above page is useful to you in keeping your computer free from unwanted adware and ensuring a safe and predictable online browsing experience.