Google Takes New Steps to Block POODLE Flaw

Google plans to disable support for SSL 3.0 in an upcoming Chrome release. Mozilla has similar intentions.

Google security

Google researchers first publicly disclosed a flaw dubbed "POODLE" in the SSL 3.0 protocol on Oct. 14. Though Google made a patch available for servers to help mitigate the risk, one of the best long-term solutions to the flaw is for browser vendors to drop support for SSL 3.0, which is now what Google is pledging to do for its Chrome browser.

The POODLE, or Padding Oracle On Downgraded Legacy Encryption, vulnerability could potentially enable an attacker to access and read encrypted communications. SSL 3.0 is a legacy protocol that has been replaced by the newer TLS 1.2 although many browser and server vendors have still supported SSL 3.0 as a fallback mechanism.

In a mailing list posting, Google developer Adam Langley wrote that for the upcoming Chrome 39 stable release, SSL 3.0 fallback will be disabled.

"SSLv3 fallback is only needed to support buggy HTTPS servers," Langley wrote. "Servers that correctly support only SSLv3 will continue to work (for now), but some buggy servers may stop working."

If a user hits a server or online application that doesn't work, due to the SSL 3.0 fallback removal, Chrome will show a yellow badge over the lock icon in the browser. By disabling the fallback and showing the yellow warning badge, Google is giving site owners a chance to update their sites before dropping SSL 3.0 entirely. The current plan is for Chrome 40 to completely disable SSL 3.0 support.

Google isn't the only browser vendor to take steps to limit the risk of POODLE. The upcoming Mozilla Firefox 34 release is also set to remove support for SSL 3.0.

Microsoft however is taking a slightly different tack for its Internet Explorer browser. There is now a "Fix it" tool from Microsoft to disable support for SSL 3.0. When POODLE was first reported on Oct. 14, Microsoft wrote in an advisory that, "considering the attack scenario, this vulnerability is not considered high risk to customers."

Apple has also taken steps to limits its users' exposure to POODLE. In its Mac OS X operating systems, Apple has not entirely blocked SSL 3.0, but rather has disabled the use of CBC, or cipher block chaining, with Secure Sockets Layer (SSL), which is at the root cause of the POODLE flaw.

Though the POODLE flaw was disclosed two weeks ago, to date there have been no public reports of any exploitation as a result of the vulnerability. In contrast, a SQL injection vulnerability reported in the open-source Drupal content management system on Oct. 15 was exploited by attackers within seven hours. The fact that POODLE has not been actively exploited is likely due to a number of factors, including very low usage of SSL 3.0. Mozilla noted when POODLE was first disclosed that SSL 3.0 only accounted for 0.3 percent of all HTTPS connections.

Sean Michael Kerner is a senior editor at eWEEK and Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.