Quick Note: Disable SSLv3 in OpenLDAP with GnuTLS

GnuTLS Logo by Claus Schrammel

Due to the SSL POODLE vulnerability, it is best to remove support for the outdated SSLv3 protocol. As OpenLDAP with GnuTLS is a beast of its own, here’s the quick change to remove SSLv3 support:

cat > nossl.ldif <<EOF
dn: cn=config
changetype: modify
add: olcTLSCipherSuite
olcTLSCipherSuite: SECURE256:-VERS-SSL3.0
EOF
ldapmodify -Y EXTERNAL -H ldapi:/// -f nossl.ldif

And we’re done! Obviously, if you already have olcTLSCipgerSuite, then use “replace” instead of “add”.

A quick test:

~# gnutls-cli-debug -p 636 127.0.0.1
Resolving '127.0.0.1'...
Connecting to '127.0.0.1:636'...
Checking for SSL 3.0 support... no
Checking whether %COMPAT is required... no
Checking for TLS 1.0 support... yes
Checking for TLS 1.1 support... yes
Checking fallback from TLS 1.1 to... N/A
Checking for TLS 1.2 support... yes