How Secure is Safari?

Apple's Safari, which runs on the Windows platform, OS X, and on iPhone and iPod Touch devices in a mobile edition, leads the browser pack in anti-phishing filtering and pop-up blocking, but also has many security weaknesses.

By Roger A. Grimes
Fri, January 30, 2009

InfoWorld — Apple's Safari, released for the Windows platform in June 2007, is the second newest browser on Windows, behind Google's Chrome. (Naturally, Apple's browser also runs on OS X, and on iPhone and iPod Touch devices in a mobile edition.) Safari leads the pack in anti-phishing filtering and pop-up blocking, but it also has many security weaknesses.

Safari can be freely downloaded from Apple's Web site, and it is offered as a default option through Apple's Software Update program, which is installed with other Apple software, including iTunes and QuickTime. Although the default Safari install is easy for end-users to unselect from Software Update, many critics assail Apple for installing potentially unwanted software during a process they believe should be used exclusively for patches and upgrades. Other observers counter that Apple's automatically pushing an opt-out product is a perfectly legitimate way to offer a free browser alternative.

[ Seealso the security reviews of Firefox, Internet Explorer, Google Chrome, and Opera. For more on browser security and protection against Web-borne threats, see the Security Adviser blog and " Test Center: Browser security tools versus the evil Web." ]

The Safari installer also installs a service called Bonjour, which allows Apple programs to advertise themselves and discover other Bonjour-compatible programs on the local network. Bonjour is used to automatically configure printers, hunt for file sharing opportunities, and find instant messaging peers, and it allows Safari to discover additional Web pages on the local network. In general, most security experts are wary of auto-discovery programs like Bonjour, and Bonjour itself has been involved in at least three known exploits. Bonjour is not essential to Safari's functionality and can be disabled.

Windows Safari

The Safari executable is not User Account Control (UAC)-aware on Windows Vista computers, but Vista automatically elevates permissions for the install because the word "setup" is in the name; this could pose a problem if Vista's heuristics detection functionality is disabled. On Windows Vista, Safari runs as a single process (Safari.exe) with DEP (Data Execution Prevention) disabled, a security negative shared only by Opera; ASLR (Address Space Layout Randomization) enabled; and file system and registry virtualization enabled, all with a MIC (Mandatory Integrity Control) level of Medium. In comparison, the rendering processes of both Internet Explorer and Google Chrome run with the more secure MIC setting of Low. Apple's Software Update checks for Safari patches once a week using a Task Scheduler job.

Safari is a full-featured browser, with common security features, including pop-up blocking, private session browsing, and an anti-phishing filter. The pop-up blocking is among the best, and the anti-phishing filter is the most accurate among the browsers I tested (Internet Explorer, Firefox, Google Chrome, and Opera). Java, JavaScript, and plug-ins can be turned off on a global basis. As with most other browsers apart from IE, Safari provides no security zones in which to place Web sites of varying degrees of trustworthiness, or to enable or disable functionality on a per-site basis.

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