Like any other thing on the internet that can be downloaded, e-books present their own risks.
If you need to download an unknown program or plugin to access the e-book then consider if it’s really necessary. Sometimes things you download carry malicious code which often ends up installing spyware on your computer.
One such example is a browser plug-in from bitroad.net. It promises to help download free e-books. In the background it installs malware.
E-books represent a large shift in technology for distributing media. Formats will continue to change, new tools will continue to be developed, and new opportunities will be found to distribute malware on the side.
So always take care what you download or install (in general, the less you install on a computer the better it’ll work). And invest in a good anti-virus package that also scans for spyware.