Don’t FREAK Out: MaxCDN Users Not Vulnerable to SSL Exploit
March 5, 2015 | Max Shubin
On March 3rd, 2015, researchers discovered a new SSL/TLS exploit termed FREAK.
FREAK uses deliberately weakened cryptography to intercept and decrypt encrypted communications. None of our customers are vulnerable to this attack, and we’re committed to preventing similar attacks from occurring in the future.
What is FREAK?
FREAK, short for “Factoring RSA-EXPORT Keys,” takes advantage of outdated rules in SSL to force a weak connection.
During SSL’s development in the 1990s, there were strong restrictions on exporting cryptographic technology outside of the United States. To comply with these restrictions, SSL’s developers included weak “export-grade” cipher suites that could be easily broken by a government organization. When the SSL library was exported overseas (e.g. as part of a web browser), these export-grade ciphers were used in place of stronger ciphers, giving government organizations access to foreign communications.
While the restrictions on exporting cryptographic software have been lifted, many browsers and servers still support export-grade ciphers. Attackers can take advantage of this to create deliberately weak connections.
How is FREAK Being Exploited?
When a web browser connects to an encrypted website, both parties negotiate and agree on a cipher suite. If an adversary intercepts the connection – performing what’s known as a man-in-the-middle (MITM) attack – he or she can negotiate an export-grade cipher with the website while using a secure cipher to communicate with the browser. The MITM can then crack the weak encryption and decrypt future communications between the browser and server.
Protecting Against FREAK
The best protection against FREAK is to avoid connecting to vulnerable websites. While browser vendors are releasing updates, several popular browsers are still susceptible to attack. As of March 5th, the browsers that are vulnerable include:
- Blackberry Browser
- Chrome on Android
- Opera on Mac OS X
- Opera on Linux
- Stock Android Browser
If you’re a web host, you should disable support for TLS export cipher suites. You can test your server for FREAK and other vulnerabilities using Qualys’ SSL Server Test tool. If your server is vulnerable, Mozilla provides a recommended configuration of cipher suites as well as an SSL configuration generator.
Update: As of March 11, Apple, Cisco, Microsoft, and Google have patched their SSL/TLS implementations against FREAK. You can use this online tool to check the current state of your browser.