Dotzler charges that Apple, Google, and Microsoft are abusing their positions as trusted software providers to sneak software onto computers without explicit user permission.
This is a longstanding issue for software makers. Recall that in 2008, Apple was accused of using its automatic update process to deliver software to Windows users without adequate notice and that it responded by changing its iTunes 8 download process.
And now the issue has resurfaced in the context of Web browser extensions. Dotzler says that installing iTunes led to the unauthorized installation of the iTunes Application Detector plug-in for Firefox, that installing Microsoft Office added the company's Windows Live Photo Gallery and Office Live plug-ins without permission, and that installing either Google Earth or Google Chrome brought the unsanctioned installation of the Google Update plug-in for Firefox.
Dotzler says such practices are unacceptable and indistinguishable from the way malicious software gets installed.
"I downloaded and installed a specific application from these vendors intending to have only that application installed, and without my consent that application foisted additional software on me," he wrote in a blog post on Sunday. "In my book, that fits the definition of a trojan horse. Yes, that is precisely how a trojan horse operates. These additional pieces of software installed without my consent may not be malicious but the means by which they were installed was sneaky, underhanded, and wrong."
Apple and Microsoft did not immediately respond to requests for comment. Google declined to comment directly, but a spokesperson pointed to Chrome's End User License Agreement.
Section 11.1 of the Chrome EULA states that Chrome "may automatically download and install updates from time to time from Google. These updates are designed to improve, enhance and further develop the Services and may take the form of bug fixes, enhanced functions, new software modules and completely new versions. You agree to receive such updates (and permit Google to deliver these to you) as part of your use of the Services."
Thus, by installing Chrome or Google Earth, both of which will install Google Update, Dotzler gave Google permission to deliver new software modules, including the Google Update extension for Firefox.