Security

Chrome periodically downloads updates of two blacklists (one for phishing and one for malware) and warns users when they attempt to visit a harmful site. This service is also made available for use by others via a free public API called "Google Safe Browsing API". In the process of maintaining these blacklists, Google also notifies the owners of listed sites who may not be aware of the presence of the harmful software.

Each tab in Chrome is sandboxed into its own process to "prevent malware from installing itself" or "using what happens in one tab to affect what happens in another". Following the principle of least privilege, each process is stripped of its rights and can compute but can not write files or read from sensitive areas (e.g. documents, desktop)—this is similar to "Protected Mode" that is used by Internet Explorer 7 on Windows Vista. The Sandbox Team is said to have "taken this existing process boundary and made it into a jail"; for example malicious software running in one tab is unable to sniff credit card numbers, interact with the mouse or tell "Windows to run an executable on start-up" and will be terminated when the tab is closed. This enforces a simple computer security model whereby there are two levels of multilevel security (user and sandbox) and the sandbox can only respond to communication requests initiated by the user.

Plugins such as Adobe Flash Player are typically not standardized and as such cannot be sandboxed like tabs. These often need to run at or above the security level of the browser itself. To reduce exposure to attack, plugins are run in separate processes that communicate with the renderer, itself operating at "very low privileges" in dedicated per-tab processes. Plugins will need to be modified to operate within this software architecture while following the principle of least privilege.

Chrome supports the Netscape Plugin Application Programming Interface (NPAPI), but does not support the embedding of ActiveX controls. Also, Chrome does not have an extension system such as Mozilla-compatible *.xpi cross-platform extension architecture and thus XPI-based extensions such as AdBlock and GreaseMonkey can not be adapted to Chrome.

Java applets support is available in Chrome as part of the pending Java 6 update 10 (which is currently in Release Candidate testing.)

A private browsing feature called Incognito mode is provided as well. It prevents the browser from storing any history information or cookies from the websites visited. This is similar to the private browsing feature in Apple's Safari.