Firefox issues security update

Mozilla released Firefox 3.0.9 yesterday, fixing more than nine security flaws - some of which were termed critical, causing crashes in Firefox 3 and, occasionally, in Firefox 2. Some of the crashes corrupted memory.

One of the issues dealt with JavaScript running in mail programs on Firefox and Thunderbird (which shares the Firefox browser engine). According to the company's website:

Mozilla developers identified and fixed several stability bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.

Thunderbird shares the browser engine with Firefox and could be vulnerable if JavaScript were to be enabled in mail. This is not the default setting and we strongly discourage users from running JavaScript in mail. Without further investigation we cannot rule out the possibility that for some of these an attacker might be able to prepare memory for exploitation through some means other than JavaScript such as large images.

Anyone who hasn't had a chance to download the update yet is advised to disable JavaScript in the meanwhile. Computer security company Secunia details the potential vulnerabilites of each flaw on its site.

pointed out this was the third update to the browser so far this year and Mozilla has pushed back release of its "Shiretoko" version of Firefox in favor of a fourth beta for Firefox 3 - Version 3.5.

The changes expected in the new beta "include faster execution of Web-based JavaScript programs, a private browsing mode, native support for the JSON (JavaScript Object Notation) technology for exchanging data between servers and browsers, and built-in audio and video abilities for bypassing Flash or other multimedia technologies."

Secunia in March issued a report that said Firefox had more security vulnerabilities last year than Internet Explorer, Safari and Opera together, but Mozilla dealt with the flaws rapidly - faster than Microsoft.

Net Applications shows Firefox has been slowly but surely edging up against Internet Explorer globally. Last May, IE had 73.75 percent of the market and Firefox had 18.41 percent. In March, IE had dropped to 66.82 percent and Firefox had risen to 22.05 percent. Safari and Chrome accounted for the rest of the difference for IE.