ISPs Meddled With Their Customers Web Traffic

About one percent of the Web pages being delivered on the Internet are being changed in transit, sometimes in a harmful way, according to researchers at the University of Washington.

In a paper, set to be delivered Wednesday, the researchers document some troubling practices. In July and August they tested data sent to about 50,000 computers and discovered that a small number of Internet service providers (ISPs) were injecting ads into Web pages on their networks. They also found that some Web browsing and ad-blocking software was actually making Web surfing more dangerous by introducing security vulnerabilities into pages.

"The Web is a lot more wild than we originally expected," said Charles Reis , a PhD student at the University of Washington who co-authored the paper.

The paper, which was co-written by a researcher at the International Computer Science Institute, will be delivered at the Usenix Symposium on Networked Systems Design and Implementation in San Francisco.