[Freeipa-users] How to turn off RC4 in 389ds???

Michael Lasevich mlasevich at gmail.com
Wed Sep 23 15:05:31 UTC 2015


Yes, I am talking about 389ds as is integrated in FreeIPA (would be silly
to post completely non-IPA questions to this list...).
I am running FreeIPA 4.1.4 on CentOS 7.1 and RC4 is enabled on port 636 no
matter what I do.

I am running "CentOS Linux release 7.1.1503 (Core)"

Relevant Packages:

freeipa-server-4.1.4-1.el7.centos.x86_64
389-ds-base-1.3.3.8-1.el7.centos.x86_64
nss-3.19.1-5.el7_1.x86_64
openssl-1.0.1e-42.el7.9.x86_64

LDAP setting (confirmed that in error.log there is no menition of RC4 in
list of ciphers):

nsSSL3Ciphers:
-rc4,-rc4export,-rc2,-rc2export,-des,-desede3,-rsa_rc4_128_md5,-rsa_rc4_128_sha,+rsa_3des_sha,-rsa_des_sha,+rsa_fips_3des_sha,+fips_3des_sha,-rsa_fips_des_sha,-fips_des_sha,-rsa_rc4_40_md5,-rsa_rc2_40_md5,-rsa_null_md5,-rsa_null_sha,-tls_rsa_export1024_with_rc4_56_sha,-rsa_rc4_56_sha,-tls_rsa_export1024_with_des_cbc_sha,-rsa_des_56_sha,-fortezza,-fortezza_rc4_128_sha,-fortezza_null,-dhe_dss_des_sha,+dhe_dss_3des_sha,-dhe_rsa_des_sha,+dhe_rsa_3des_sha,+tls_rsa_aes_128_sha,+rsa_aes_128_sha,+tls_dhe_dss_aes_128_sha,+tls_dhe_rsa_aes_128_sha,+tls_rsa_aes_256_sha,+rsa_aes_256_sha,+tls_dhe_dss_aes_256_sha,+tls_dhe_rsa_aes_256_sha,-tls_dhe_dss_1024_rc4_sha,-tls_dhe_dss_rc4_128_sha

Slapd "error" log showing no ciphersuites supporting RC4:

[23/Sep/2015:08:51:04 -0600] SSL Initialization - Configured SSL version
range: min: TLS1.0, max: TLS1.2
[23/Sep/2015:08:51:04 -0600] - SSL alert: Cipher suite fortezza is not
available in NSS 3.16.  Ignoring fortezza
[23/Sep/2015:08:51:04 -0600] - SSL alert: Cipher suite fortezza_rc4_128_sha
is not available in NSS 3.16.  Ignoring fortezza_rc4_128_sha
[23/Sep/2015:08:51:04 -0600] - SSL alert: Cipher suite fortezza_null is not
available in NSS 3.16.  Ignoring fortezza_null
[23/Sep/2015:08:51:04 -0600] - SSL alert: Configured NSS Ciphers
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_DHE_RSA_WITH_AES_128_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_DHE_DSS_WITH_AES_128_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_DHE_RSA_WITH_AES_256_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_DHE_DSS_WITH_AES_256_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_RSA_WITH_AES_128_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - SSL alert:
TLS_RSA_WITH_AES_256_CBC_SHA: enabled
[23/Sep/2015:08:51:04 -0600] - 389-Directory/1.3.3.8 B2015.040.128 starting
up

But sslscan returns:

$ sslscan --no-failed localhost:636
...

Supported Server Cipher(s):

    Accepted  TLSv1  256 bits  AES256-SHA
    Accepted  TLSv1  128 bits  AES128-SHA
    Accepted  TLSv1  128 bits  DES-CBC3-SHA
    Accepted  TLSv1  128 bits  RC4-SHA
    Accepted  TLSv1  128 bits  RC4-MD5
    Accepted  TLS11  256 bits  AES256-SHA
    Accepted  TLS11  128 bits  AES128-SHA
    Accepted  TLS11  128 bits  DES-CBC3-SHA
    Accepted  TLS11  128 bits  RC4-SHA
    Accepted  TLS11  128 bits  RC4-MD5
    Accepted  TLS12  256 bits  AES256-SHA256
    Accepted  TLS12  256 bits  AES256-SHA
    Accepted  TLS12  128 bits  AES128-GCM-SHA256
    Accepted  TLS12  128 bits  AES128-SHA256
    Accepted  TLS12  128 bits  AES128-SHA
    Accepted  TLS12  128 bits  DES-CBC3-SHA
    Accepted  TLS12  128 bits  RC4-SHA
    Accepted  TLS12  128 bits  RC4-MD5

...


I would assume the sslscan is broken, but nmap and other scanners all
confirm that RC4 is still on.

-M

On Wed, Sep 23, 2015 at 3:35 AM, Martin Kosek <mkosek at redhat.com> wrote:

> On 09/23/2015 11:00 AM, Michael Lasevich wrote:
> > OK, this is most bizarre issue,
> >
> > I am trying to disable RC4 based TLS Cipher Suites in LDAPs(port 636) and
> > for the life of me cannot get it to work
> >
> > I have followed many nearly identical instructions to create ldif file
> and
> > change "nsSSL3Ciphers" in "cn=encryption,cn=config". Seems simple enough
> -
> > and I get it to take, and during the startup I can see the right SSL
> Cipher
> > Suites listed in errors.log - but when it starts and I probe it, RC4
> > ciphers are still there. I am completely confused.
> >
> > I tried setting "nsSSL3Ciphers" to "default" (which does not have "RC4")
> > and to old style cyphers lists(lowercase), and new style cypher
> > lists(uppercase), and nothing seems to make any difference.
> >
> > Any ideas?
> >
> > -M
>
> Are you asking about standalone 389-DS or the one integrated in FreeIPA? As
> with currently supported versions of FreeIPA, RC4 ciphers should be already
> gone, AFAIK.
>
> In RHEL/CentOS world, it should be fixed in 6.7/7.1 or later:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1154687
> https://fedorahosted.org/freeipa/ticket/4653
>
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