Something as simple as opening a PDF file can infect your computer, and potentially allow malicious hackers to gain access to your corporate network.

Cybercriminals create boobytrapped PDF files, exploiting vulnerabilities in PDF reading software such as Adobe Reader, and either spam them out to unsuspecting victims or plant them on websites where they lie in wait for visitors.
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Several media organizations have recently reported that Chrome has bypassed Internet Explorer in worldwide browser market share.

Here at Sophos, we don't keep track of that sort of thing, but we have seen a major change in browser marketing over the last 24 months. The browser makers are selling security.
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A number of websites associated with US police have been compromised by AntiSec hackers in apparent support of the "Occupy" demonstrations.

One of the sites targeted was the Boston Police Patrolmen's Association (BPPA), which suffered a hack which resulted in the release of a thousand usernames and passwords. ...