Last week, security researchers at Google published details of a vulnerability in the design of SSL version 3.0, which they’ve named POODLE (Padding Oracle On Downgraded Legacy Encryption, CVE-2014-3566). The vulnerability allows an attacker to decrypt secure connections, potentially allowing the interception of session cookies etc. within HTTPS connections.
SSLv3 is nearly 18 years old and has been deprecated, in favour of TLS, for almost as long but it is still quite widespread. What makes matters worse is an attacker can force a TLS connection to be downgraded to SSL, where it can then be intercepted.
There are two main solutions to the problem. You could just disable SSL on your servers and only support TLS. Unfortunately, some older browsers (particularly IE6) that do not support TLS are still in use and will be unable to connect.
Another solution is to upgrade your servers to support the new
TLS_FALLBACK_SCSV feature, which stops an attacker being able to downgrade a connection from TLS to SSL, but still allows you to support SSL for older clients. This requires browsers and clients to be upgraded to be effective, but most browsers and operating systems are rolling that out now.
For our own services, such as our websites and API, we’re disabling SSLv3 support and requiring TLS. None of our customers are using Internet Explorer 6 and our CLI and API libraries all support TLS by default.
And as of today, we’ve upgraded all existing customer load balancers to support
TLS_FALLBACK_SCSV to help prevent downgrade attacks.
We’re also introducing an option to disable SSLv3 in load balancers via the API. All new load balancers will have SSLv3 disabled unless you specifically enable it. You can disable it in your existing load balancers by editing them in the Brightbox Manager and unticking the SSLv3 option in the SSL tab (you can do the same using the CLI too). This option is now in the API and will be available in the Brightbox Manager GUI and CLI by tomorrow.
So in summary, disable SSLv3 anywhere you don’t mind losing some backwards compatibility for older browsers. Otherwise, ensure you’ve applied the relevant
TLS_FALLBACK_SCSV security updates.