Weblogs are spreading more than opinions and observations across the Internet. Some are beginning to propagate malicious software downloads that can alter browser settings, track users and serve pop-up ads.
Dozens of blogs hosted by Google Inc.s Blogger service can install programs that are widely considered to be spyware and adware onto visitors computers, warn users and spyware researchers. In many cases, users are discovering the offending sites as they browse among blogs through Bloggers navigation bar.
The offending blogs typically prompt visitors to accept downloads through misleading pop-up windows, said Ben Edelman, a vocal spyware critic and Harvard University researcher. While a user typically must accept the download before the software installs, the prompts often attempt to trick users by disguising the download as a necessary Windows or Internet Explorer upgrade.
Edelman, who on Tuesday posted the results of his tests, discovered dozens of Blogger-hosted blogs spreading spyware and adware programs such as Elitetoolbar, Crazywinnings and DirectRevenue. For example, security vendors such as Symantec Corp. classify Elitetoolbar, or EliteBar, as adware because it installs an Internet Explorer tool bar, redirects search queries and initiates pop-up ads.
A Google spokesperson Tuesday confirmed that Blogger was aware of the spyware issue but declined to provide details about how the company plans to address it.
"We are aware of this issue, and we are looking into it," the spokesperson said.
One victim of spyware from a Blogger-hosted blog was attorney Alvin Borromeo of Columbus, Ohio. He first wrote about the problem in a post in January on the blog of his law firm, Mallory & Tsibouris Co. LPA. Last week, he posted an update with details of Bloggers reply to his inquiries.
Borromeo reached a blog that installed spyware on his Windows computer after clicking the "Next Blog" link in the Blogger navigation bar, he said. He then noticed pop-up ads appearing and that his Internet Explorer home page was changed.
Blogger in August had introduced the navigation bar atop blogs that it hosts. The bar is optional for Blogger users with their own Web hosting.
"It was very surprising," Borromeo said. "Its something that youd expect that Google would be up on, and it came as a shock to me that I would get [spyware] through this avenue."
Borromeo added a warning to the law firms blog about the potential for spyware downloads when navigating blogs and later moved his blog to the firms own host in order to remove the Blogger navigation bar.
"I dont want my users going onto my blog and then clicking that next link and getting spyware downloaded onto their system," Borromeo said.
A Google search on iWebTunes and Blogspot, the name of Bloggers hosting service, yields pages of blog results. When eWEEK.com visited about five of the blogs, they displayed pop-ups in Internet Explorer with misleading prompts to accept downloads.
When one download was accepted, it installed the EliteBar, which disabled other IE tool bars, including the Google Toolbar; changed the browser home page to SearchMiracle.com and began displaying pop-up ads even when IE was closed.
Both Edelman and Borromeo were critical of Blogger for being slow to deal with the spyware and adware issues. Both said they have contacted Blogger with the addresses of specific blogs with spyware and adware downloads, but so far none of those blogs has been fixed or removed.