Late last week, a new SSL bug was discovered by Google Research Labs. Simply put, due to the large number of protocols, clients and servers, most clients will start with the highest supported protocol and downgrade accordingly in order to be compatible to older servers. The weakness happens in SSLv3 which is 18 years old which can allow an attacker with sufficient computing resources to guess the encrypted data. For the more technical reader, here’s a link with more details.
While exploiting this bug is fairly difficult due to the large amount of computing resources needed, once the exploit was known, our team started putting together an action plan within hours. We started off implementing a patched version of OpenSSL on all servers which support TLS_FALLBACK_SCSV. This is a mechanism that solves the problems caused by retrying failed connections and thus prevents attackers from inducing browsers to use SSL 3.0. It also prevents downgrades from TLS 1.2 to 1.1 or 1.0 and so may help prevent future attacks.
However we did not stop there. We continue to refine our response and came out with methods to disable SSLv3 on all the main servers on our clients and our own servers. This includes:
- Apache Web Server
- WHM / Cpanel Control Panel
- POP3 / IMAP Mail server
- Exim SMTP server
This ensures that SSLv3 is no longer available to be exploited even if there’s some still unknown method to exploit it.
While this may break support for older clients, we estimated this to be of very limited impact. The security advantages also fair outweighs the disadvantages. If in doubt, please feel free to contact our support team.
What is it?
Chances are, you’ve already heard about the recent discovery of what’s being called the “Heartbleed” bug in OpenSSL. Basically, this is a vulnerability that existed in OpenSSL for around 2+ years. The vulnerability caused by a gap where encrypted information could potentially be leaked out to hackers. It is important to note that this is NOT due to a flaw in SSL, but rather the platform and implementation of the latest batch of OpenSSL updates.
The Heartbleed bug allows anyone on the Internet to read the memory of the systems protected by the vulnerable versions of the OpenSSL software. This compromises the secret keys used to identify the service providers and to encrypt the traffic, the names and passwords of the users and the actual content. This allows attackers to eavesdrop on communications, steal data directly from the services and users and to impersonate services and users.
Given the widespread use of OpenSSL on the internet as the implementation for SSL, and the fact that the bug has been in the wild for years, this means that it is possible that a lot of sensitive information may have been stolen by hackers.
Am I affected?
For servers running RHEL/CentOS 5, the version of OpenSSL used is not affected. For servers running RHEL/CentOS 6, the bug was patched the same day the bug was made public. For all servers managed and hosted with us, we have automatically patched the bug the day it was made public on affected servers. However this does mean that you are not vulnerable to the issue. The key used for your SSL certificates may have already been stolen in the time the bug is in the wild.
For safety, if you are running RHEL/CentOS 6, you are recommended to rekey your domain and request for a reissue of the certificate. If you ordered the certificate from us, we will be regenerating the keys and reissuing the certificates automatically as well.
Personally if you have changed your passwords on any affected sites over the past 2 years, you are encouraged to confirm that the affected site have updated their certificates and change your passwords again.