The move to 64-bit software has been steady (if slow), but browsers are in their own category entirely.
- Microsoft has been offering a 64-bit version of Internet Explorer (IE6 and up) since the release of the 64-bit versions of Windows XP and Windows Server 2003 in April 2005.
- A 64-bit version of Safari is available in Snow Leopard, and Linux users can download a 64-bit version of Opera.
- Chrome, however, doesn’t yet have a 64-bit version.
- Firefox has one, but only for Linux (unofficial 64-bit versions of Firefox exist for Windows and Mac).
So why haven’t Mozilla and Google bothered to release official 64-bit browsers? For the same reason Microsoft hasn’t bothered to produce a 64-bit version of its Silverlight plug-in: nobody uses 64-bit browsers and Businesses aren’t asking for 64-bit."
There are three key plug-ins that need to offer 64-bit versions before mainstream users can switch. In order of importance, these are:
- Flash,
- Java and
- Silverlight
"Users are running 32-bit browsers because of plugins. It’s all about sequencing and timing. We’re absolutely going to do it; we’re just not going to do it yet." Based on the data Microsoft was seeing, 64-bit browser support just wasn’t worth the effort
Java, on the other hand, added 64-bit support 12 months ago: Java SE 6 Update 12 was released in January 2009 (almost four years after the first 64-bit version of IE arrived).
Flash, arguably the most important plugin for day-to-day browsing, doesn’t have any 64-bit support except for an alpha Linux version released in November 2008. The only official statement the company offers on its website is a TechNote titled Flash Player support on 64-bit operating systems, which was updated on October 21, 2009:
Issue: Adobe Flash Player is not supported for playback in a 64-bit browser. However, you can run Flash Player in a 32-bit browser running on a 64-bit operating system.
Reason: Adobe is working on Flash Player support for 64-bit platforms as part of our ongoing commitment to the cross-platform compatibility of Flash Player. We expect to provide native support for 64-bit platforms in an upcoming release of Flash Player following the release of Flash Player 10.1.
Why use 64-bit browsers anyway?
While a move to 64 bits doesn’t noticeably impact browser performance, 64-bit browsers are more secure… at least for now.
"Security is a huge priority for us, and Silverlight has had virtually no security issues," Goldfarb noted. He also agreed that there is clearly a temporary gain for switching to 64-bit browsers; eventually malware writers will go where the majority of users are anyway. There really wouldn’t be much of a long-term gain, but the short-term gain, which could last a few years, is worth the effort since the larger majority of malware is written with the assumption the targeted browser is 32-bit.
Furthermore, techniques such as Address Space Layout Randomization (ASLR), a security technique which involves randomly arranging the positions of key data areas in memory to thwart hacking, can currently be defeated on 32-bit browsers through techniques such as heap-spraying, which some exploits use to execute arbitrary code. Malicious programs can thus fill the program’s address space with malicious code so that even if a random memory address is chosen, there is still an excellent chance that the exploit code is executed. Heap-spraying and other malware methods aren’t as viable with a large, 64-bit memory space.
Reference: Why there’s no 64-bit Silverlight from Microsoft… yet
