"Starting last September, Lenovo has shipped notebooks with the adware program Superfish pre-installed. The program reportedly injects ads into Google search results. Lenovo says its goal was “to help customers potentially discover interesting products while shopping.”

But it emerged last night that the adware has some unintended consequences. Superfish -- “a horrifically dangerous piece of software,” according to the Electronic Frontier Foundation -- also leaves users vulnerable to hackers.

That's because the program tinkers with Windows' cryptographic security, in order to inject ads into secure HTTPS pages. “Lenovo has not just injected ads in a wildly inappropriate manner, but engineered a massive security catastrophe for its users,” the EFF says. “If you access your webmail from such a laptop, any network attacker can read your mail as well or steal your password. If you log into your online banking account, any network attacker can pilfer your credentials.”"
Full article:
Lenovo Notebooks Come With 'Horrifically Dangerous' Adware 02/19/2015

EFF article: