Typhoid adware is a type of computer security threat that uses a Man-in-the-middle attack to inject advertising into web pages a user visits when using a public network, like a Wi-Fi hotspot. Researchers from the University of Calgary identified the issue, which does not require the affected computer to have adware installed in order to display advertisements on this computer. The researchers said that the threat was not yet observed, but described its mechanism and potential countermeasures.