FREAK attack: How to keep your code secure
- 05 March, 2015 07:21
Bill Weinberg, Senior Director, Open Source Strategy, Black Duck Software
Remember the 1990s, when the Netscape browser was all the rage and Secure Socket Layer (SSL) encryption was a brand-new idea? Back then, the U.S. government wanted to control the export of "weapons grade" encryption. Its theory was that domestic communications could benefit from stronger, 128-bit encryption, but "backdoors" should be available to U.S. intelligence and law enforcement when it came to foreign communications. Thus, the concept of weaker, "export grade" encryption was born.
Fast forward to 2015 and it turns out that this legacy backdoor, a vulnerability that we've come to know as "The FREAK Attack," still exists in anywhere from a quarter to a third of all deployed web servers. It's a sad example of how zombie security holes from the era of grunge fashion can return to bite us. The question is: what to do now and how can you ensure your code is safe?
Here's the lowdown: FREAK appears to impact code from the OpenSSL project (as Heartbleed did last year). It appears that different browsers are affected differently: Safari and most Android-native browsers are vulnerable, but Chrome is not. These web clients all build on open source but make use of different versions of OpenSSL and employ different web application tool kits (Apple says it is preparing a patch).
The vulnerability allows attackers to intercept HTTPS connections between vulnerable clients and servers and force them to use the weaker export-grade encryption, which can then be decrypted or altered. Many Google and Apple devices are potentially affected, along with embedded systems. FREAK was originally discovered by researchers at INRIA, a computer science research organization headquartered in Paris.
Computer scientists at the University of Michigan are maintaining a site that details the history of the attack and provides useful tips on remediation. Here's what they recommend:
"If you run a web server, you should disable support for any export suites. However, instead of simply excluding RSA export cipher suites, we encourage administrators to disable support for all known insecure ciphers (e.g., there are export cipher suites protocols other than RSA) and enable forward secrecy. Mozilla has published a guide and SSL Configuration Generator, which will generate known good configurations for common servers. You can check whether your site is vulnerable using the SSL Labs' SSL Server Test."
With additional web server fixes expected from a number of vendors, it appears the FREAK Attack story is far from over. It's a useful reminder that a lot of legacy code, while largely vanished from memory, isn't forgotten when it comes to the systems we continue to use every day.