[Pkg-openssl-devel] Bug#778747: openssl: RFC 7465 says RC4 is broken, never to be used

[Sebastian Andrzej Siewior]

On 2015-02-22 11:44:37 [+0100], Kurt Roeckx wrote:
> Even with RC4 enabled on both sides, it does provide something
> secure that doesn't use RC4 as long as you don't don't touch the
> defaults.  And I've seen many applications that screw up the
> defaults.

As of openssl in experimental we don't have RC4 in list of default
ciphers. The bug reported wants RC4 removed from openssl so my
understanding is that adding RC4 to the cipher's list should not result
in RC4 being available. Is that so?

If so lets continue…
We can't remove RC4 completly from openssl. From codesearch.d.n I see
that hydra and kismet are using it. I am not sure how much good we do if
they stop building.

Someone said that here that major browser vendors offer RC4. So I
checked them and can say that this is no longer an argument:

Chrome 50 (sid)
  TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
  TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
  TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
  TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
  TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  TLS_RSA_WITH_AES_128_GCM_SHA256
  TLS_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_AES_128_CBC_SHA
  TLS_RSA_WITH_3DES_EDE_CBC_SHA

Firefox 45.1.1 (sid):
  TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_AES_128_CBC_SHA
  TLS_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_3DES_EDE_CBC_SHA

Win XP, IE 8 (fully patched):
  TLS_RSA_WITH_RC4_128_MD5
  TLS_RSA_WITH_RC4_128_SHA
  TLS_RSA_WITH_3DES_EDE_CBC_SHA
  TLS_RSA_WITH_DES_CBC_SHA
  TLS_RSA_EXPORT1024_WITH_RC4_56_SHA
  TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA
  TLS_RSA_EXPORT_WITH_RC4_40_MD5
  TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5
  TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
  TLS_DHE_DSS_WITH_DES_CBC_SHA
  TLS_DHE_DSS_EXPORT1024_WITH_DES_CBC_SHA

Win XP, Firefox 45.1.1 (ESR)
  TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_AES_128_CBC_SHA
  TLS_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_3DES_EDE_CBC_SHA

Win XP, Firefox 38.8 (ESR, lowest major supported)
  TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_AES_128_CBC_SHA
  TLS_RSA_WITH_AES_256_CBC_SHA
  TLS_RSA_WITH_3DES_EDE_CBC_SHA

Win XP, Opera 36.0
 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 TLS_RSA_WITH_AES_128_GCM_SHA256
 TLS_RSA_WITH_AES_256_CBC_SHA
 TLS_RSA_WITH_AES_128_CBC_SHA
 TLS_RSA_WITH_3DES_EDE_CBC_SHA

So. As of today RC4 isn't offerred by browsers except for IE4 on WinXP.
Firefox gone, Chromium gone. It remains only on XP with IE8 which has
_no_ support from its vendor so…

Kurt mentioned some broken exchange servers which do only RC4. Is this
still an issue? But this is SMTP only, right? So if the sender drops SSL
then everything works in plain text and there is no problem?

> Kurt

Sebastian