I'm by no means a crypto expert. Still I'm frequently getting (and answering) questions regarding the use of RC4 in SSL/TLS. Should you disable it? Or keep it enabled?
March 2015 update - A 'new' attack method (Bar Mitsvah Attack) using a previously known RC4 vulnerability was presented, thereby reducing the RC4 security even more.
February 2015 update - RFC 7456 has been published, which effectively prohibits the use of RC4 in TLS.
This document requires that Transport Layer Security (TLS) clientsand servers never negotiate the use of RC4 cipher suites when theyestablish connections. This applies to all TLS versions.
Here is my reasoning to disable all ciphersuites using RC4:
- RC4 is a stream cipher that has been around since 1987. The number and quality of attacks on RC4 (in SSL/TLS) increases. Fact: Attacks on encryption algorithms only get better, they never get worse.
- A lot of sites still enable RC4 in their ciphers, to support a wide browser base. Fact: Even Internet Explorer on Windows XP supports DES-CBC3-SHA (an alternative to one of the RC4 ciphers)
- RC4 is one of the few ciphers that is resistant to the BEAST attack …