Security Expert: Yahoo's Email Encryption Needs Work

itwbennett writes "On Tuesday, Yahoo delivered on a promise that it made in October to enable email encryption for everyone by default by January 8. While this is a great step, the company's HTTPS implementation appears to be inconsistent across servers and even technically insecure in some cases, according to Ivan Ristic, director of application security research at security firm Qualys. For example, some of Yahoo's HTTPS email servers use RC4 as the preferred cipher with most clients. 'RC4 is considered weak, which is why we advise that people either don't use it, or if they feel they must, use it as a last resort,' Ristic said."

Comments

"[U]se [RC4] as a last resort."

[cffrost]

Unfortunately — in Firefox, at least — ciphers can only be toggled, not given a priority. Control over cipher selection (and other HTTPS parameters, such as key length, key exchange, hash (MD5/SHA)., etc.) lies with the server operator. In my own testing, the arbitrated HTTPS parameters are most frequently prioritized in some order without regard to strength, or prioritized from weakest-to-strongest (or perhaps least-to-most expensive to execute).

In order to retain manageable security, I have only TLS 1.0-1.2 enabled, MD5 disabled, all RC4-employing combos disabled, with the last being switchable via a check box provided by "CipherFox." (Additional features of use to "CipherFox" users are provided by "Calomel SSL Validation."; I recommend both.)

This is not "email encryption"

[daveewart]

While the article is correct and uses precise terminology, the summary is wrong to use the term "email encryption". That term is for encrypted email messages using PGP/GPG/S-MIME.

Yahoo have no framework for email encryption. This article is about use of HTTPS for their webmail service and (a) whether that has been implemented and, if so, (b) whether it has been done correctly.

The answers to which are: (a) mostly and (b) no.