On Fri, Jul 31, 2015 at 06:43:18PM +0000, Felix Almeida wrote:
> I was trying to establish a secure connection from an old Linux box to an
> internal AD server (via LDAPS) but it was failing during the handshake.
> The AD server accepts SSL2, SSL3 and TLS1.
Is it Windows server 2003? It likely only supports RC4 and 3DES, and only
if these appear in the first 64 elements of the client's cipherlist.
When a TLS 1.2 handshake is sent, may newer ciphers appear before the server's
RC4 and 3DES (the latter is broken in Microsoft Exchange on Windows 2003, but
may work with LDAP).
> However, if I add any of the following command line options then it works: -ssl2, -ssl3, -tls1, -no_tls1, -no_tls1_1, -no_tls1_2.
All these disable TLS 1.2 (and perhaps other protocol versions), and result
in a shorter cipherlist.
> SSL-Session:
> Protocol : TLSv1
> Cipher : RC4-MD5
Bingo: RC4-MD5, it likely also supports RSA-SHA. Here's a sensibly
trimmed, but widely interoperable cipherlist:
$ c='HIGH:MEDIUM:@STRENGTH:+3DES:+RC4:!aNULL:!MD5:!SRP:!PSK:!aDSS:!kECDH:!kDH:!SEED,!IDEA:!RC2:!RC5'
$ openssl s_client -cipher "$c" ...
The resulting cipherlist with OpenSSL 1.0.2 is:
1:ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD
2:ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(256) Mac=AEAD
3:ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(256) Mac=SHA384
4:ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(256) Mac=SHA384
5:ECDHE-RSA-AES256-SHA SSLv3 Kx=ECDH Au=RSA Enc=AES(256) Mac=SHA1
6:ECDHE-ECDSA-AES256-SHA SSLv3 Kx=ECDH Au=ECDSA Enc=AES(256) Mac=SHA1
7:DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(256) Mac=AEAD
8:DHE-RSA-AES256-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AES(256) Mac=SHA256
9:DHE-RSA-AES256-SHA SSLv3 Kx=DH Au=RSA Enc=AES(256) Mac=SHA1
10:DHE-RSA-CAMELLIA256-SHA SSLv3 Kx=DH Au=RSA Enc=Camellia(256) Mac=SHA1
11:AES256-GCM-SHA384 TLSv1.2 Kx=RSA Au=RSA Enc=AESGCM(256) Mac=AEAD
12:AES256-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA256
13:AES256-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(256) Mac=SHA1
14:CAMELLIA256-SHA SSLv3 Kx=RSA Au=RSA Enc=Camellia(256) Mac=SHA1
15:ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128) Mac=AEAD
16:ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(128) Mac=AEAD
17:ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(128) Mac=SHA256
18:ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(128) Mac=SHA256
19:ECDHE-RSA-AES128-SHA SSLv3 Kx=ECDH Au=RSA Enc=AES(128) Mac=SHA1
20:ECDHE-ECDSA-AES128-SHA SSLv3 Kx=ECDH Au=ECDSA Enc=AES(128) Mac=SHA1
21:DHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AESGCM(128) Mac=AEAD
22:DHE-RSA-AES128-SHA256 TLSv1.2 Kx=DH Au=RSA Enc=AES(128) Mac=SHA256
23:DHE-RSA-AES128-SHA SSLv3 Kx=DH Au=RSA Enc=AES(128) Mac=SHA1
24:DHE-RSA-CAMELLIA128-SHA SSLv3 Kx=DH Au=RSA Enc=Camellia(128) Mac=SHA1
25:AES128-GCM-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AESGCM(128) Mac=AEAD
26:AES128-SHA256 TLSv1.2 Kx=RSA Au=RSA Enc=AES(128) Mac=SHA256
27:AES128-SHA SSLv3 Kx=RSA Au=RSA Enc=AES(128) Mac=SHA1
28:CAMELLIA128-SHA SSLv3 Kx=RSA Au=RSA Enc=Camellia(128) Mac=SHA1
29:ECDHE-RSA-DES-CBC3-SHA SSLv3 Kx=ECDH Au=RSA Enc=3DES(168) Mac=SHA1
30:ECDHE-ECDSA-DES-CBC3-SHA SSLv3 Kx=ECDH Au=ECDSA Enc=3DES(168) Mac=SHA1
31:EDH-RSA-DES-CBC3-SHA SSLv3 Kx=DH Au=RSA Enc=3DES(168) Mac=SHA1
32:DES-CBC3-SHA SSLv3 Kx=RSA Au=RSA Enc=3DES(168) Mac=SHA1
33:ECDHE-RSA-RC4-SHA SSLv3 Kx=ECDH Au=RSA Enc=RC4(128) Mac=SHA1
34:ECDHE-ECDSA-RC4-SHA SSLv3 Kx=ECDH Au=ECDSA Enc=RC4(128) Mac=SHA1
35:RC4-SHA SSLv3 Kx=RSA Au=RSA Enc=RC4(128) Mac=SHA1
Your LDAP server will choose #35: RC4-SHA. Other servers will make
better choices, and nothing remotely mainstream or required for
interoperability is excluded.
--
Viktor.
