Bad guys trick you into installing and running this kind of software by bundling it with something you might want, like a free screensaver, a video plugin or—ironically—a supposed security update. These malicious programs disguise themselves so you won’t know they’re there and they may change your homepage or inject ads into the sites you browse. Worse, they block your ability to change your settings back and make themselves hard to uninstall, keeping you trapped in an undesired state.
We're taking steps to help, including adding a "reset browser settings" button in the last Chrome update, which lets you easily return your Chrome to a factory-fresh state. You can find this in the “Advanced Settings” section of Chrome settings.
In the current Canary build of Chrome, we’ll automatically block downloads of malware that we detect. If you see this message in the download tray at the bottom of your screen, you can click “Dismiss” knowing Chrome is working to keep you safe.
This is in addition to the 10,000 new websites we flag per day with Safe Browsing, which also detects and blocks malicious downloads, to keep more than 1 billion web users safe across multiple browsers that use this technology. Keeping you secure is a top priority, which is why we’re working on additional means to stop malicious software installs as well.
Update: 11/1/13: Updated to mention that Safe Browsing already detects and blocks malware.
Linus Upson, Vice President