Microsoft today took another step in a drawn-out move to protect Internet Explorer 11 (IE11) against POODLE attacks, and said it would finally disable SSL 3.0 in the browser in April.
In October 2014, a team of Google security researchers disclosed a 15-year-old flaw in SSL 3.0 -- an aged standard used to encrypt traffic between browsers and Web servers -- and dubbed attacks exploiting the bug as POODLE, for Padding Oracle On Downgraded Legacy Encryption. Criminals could make off with session cookies with a "man-in-the-middle" attack; those cookies would then let the hackers impersonate victims, automatically logging onto sites to buy goods, snoop through email or steal files from cloud storage services.
Web browsers were designed to use newer versions of SSL or the successor, TLS (Transport Layer Security), but before the Google team's revelation most also accommodated SSL 3.0 if that's all a server offered.
With Tuesday's update to IE11, the browser is now set to stymie by default what's called "SSL 3.0 fallback," a mechanism that forces the browser to switch to the buggy SSL 3.0 from more secure encryption protocols, such as TLS 1.2.
In December, an IE11 update offered the kill-SSL-fallback only as an option.
With another update now slated for April 14 -- that month's Patch Tuesday -- Microsoft will completely disable SSL 3.0, the final step in its defensive change.
Rival browser makers moved much faster than Microsoft to dump SSL 3.0.
Mozilla disabled SSL 3.0 in Firefox 34, which was released in November 2014, and Google did the same with Chrome 40, issued on Jan. 21, 2015. Apple has not yet ditched SSL 3.0. Instead, it blocked Safari's use of potentially-vulnerable cryptographic ciphers last year.
Microsoft's slow climb onto the "kill-SSL 3.0" bandwagon reflected its conservative approach to most browser problems, a necessity since the bulk of IE users run it in business settings. Corporations are notoriously adverse to change, and would raise Cain if Microsoft suddenly tossed the protocol, preventing workers from reaching required websites.
Also of interest, the changes have been, and in April will be, made only in IE11, not in earlier editions of the browser. Although that has left a majority of IE users vulnerable -- in January, IE11 accounted for just 38% of all copies of IE tracked by metrics company Net Applications -- Microsoft has tapped IE11 as its primary browser for the future. In August 2014, Microsoft abruptly announced that it was giving customers until January 2016 to stop using older versions of IE.
After Jan. 12, 2016, Microsoft will support only IE11 on Windows 7, 8 and 8.1. (Microsoft will bundle IE with Windows 10, along with a new browser code named "Spartan," but it has not said what version that IE will be labeled.) Other browsers will no longer receive security patches.
Today's IE11 update was one of nine Microsoft issued Tuesday. Designated MS15-009, it patched 41 vulnerabilities in the browser line. The update can be retrieved through the Windows Update service or the business-grade Windows Server Update Services (WSUS).