Remove TLS 1.0 as a default SSL protocol (#37512)

The default value for ssl.supported_protocols no longer includes TLSv1
as this is an old protocol with known security issues.
Administrators can enable TLSv1.0 support by configuring the
appropriate `ssl.supported_protocols` setting, for example:

xpack.security.http.ssl.supported_protocols: ["TLSv1.2","TLSv1.1","TLSv1"]

Relates: #36021

docs/reference/migration/migrate_7_0/settings.asciidoc

@@ -132,6 +132,19 @@ fallback to a default configuration when using TLS. Each component (realm, trans
 http client, etc) must now be configured with their own settings for TLS if it is being
 used.
 
+[float]
+[[tls-v1-removed]]
+==== TLS v1.0 disabled
+
+TLS version 1.0 is now disabled by default as it suffers from
+https://www.owasp.org/index.php/Transport_Layer_Protection_Cheat_Sheet#Rule_-_Only_Support_Strong_Protocols[known security issues].
+The default protocols are now TLSv1.2 and TLSv1.1.
+You can enable TLS v1.0 by configuring the relevant `ssl.supported_protocols` setting to include `"TLSv1"`, for example:
+[source,yaml]
+--------------------------------------------------
+xpack.security.http.ssl.supported_protocols: [ "TLSv1.2", "TLSv1.1", "TLSv1" ]
+--------------------------------------------------
+
 [float]
 [[watcher-notifications-account-settings]]
 ==== Watcher notifications account settings

docs/reference/settings/security-settings.asciidoc

@@ -480,7 +480,7 @@ and `full`. Defaults to `full`.
 See <<ssl-tls-settings,`ssl.verification_mode`>> for an explanation of these values.
 
 `ssl.supported_protocols`::
-Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.2,TLSv1.1,TLSv1`.
+Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.2,TLSv1.1`.
 
 `ssl.cipher_suites`:: Specifies the cipher suites that should be supported when 
 communicating with the LDAP server. 
@@ -724,7 +724,7 @@ and `full`. Defaults to `full`.
 See <<ssl-tls-settings,`ssl.verification_mode`>> for an explanation of these values.
 
 `ssl.supported_protocols`::
-Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.2, TLSv1.1, TLSv1`.
+Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.2, TLSv1.1`.
 
 `ssl.cipher_suites`:: Specifies the cipher suites that should be supported when 
 communicating with the Active Directory server. 
@@ -1206,8 +1206,7 @@ settings. For more information, see
 
 `ssl.supported_protocols`::
 Supported protocols with versions. Valid protocols: `SSLv2Hello`,
-`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`. Defaults to `TLSv1.2`, `TLSv1.1`,
+`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`. Defaults to `TLSv1.2`, `TLSv1.1`. 
-`TLSv1`. 
 +
 --
 NOTE: If `xpack.security.fips_mode.enabled` is `true`, you cannot use `SSLv2Hello` 

docs/reference/settings/ssl-settings.asciidoc

@@ -11,8 +11,8 @@ endif::server[]
 
 +{ssl-prefix}.ssl.supported_protocols+::
 Supported protocols with versions. Valid protocols: `SSLv2Hello`,
-`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`. Defaults to `TLSv1.2`, `TLSv1.1`,
+`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`. Defaults to `TLSv1.2`, `TLSv1.1`.
-`TLSv1`.
+
 
 ifdef::server[]
 +{ssl-prefix}.ssl.client_authentication+::

libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/SslConfigurationLoader.java

@@ -68,7 +68,7 @@ import static org.elasticsearch.common.ssl.SslConfigurationKeys.VERIFICATION_MOD
  */
 public abstract class SslConfigurationLoader {
 
-    static final List<String> DEFAULT_PROTOCOLS = Arrays.asList("TLSv1.2", "TLSv1.1", "TLSv1");
+    static final List<String> DEFAULT_PROTOCOLS = Arrays.asList("TLSv1.2", "TLSv1.1");
     static final List<String> DEFAULT_CIPHERS = loadDefaultCiphers();
     private static final char[] EMPTY_PASSWORD = new char[0];
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackSettings.java

@@ -154,7 +154,7 @@ public class XPackSettings {
         }
     }, Setting.Property.NodeScope);
 
-    public static final List<String> DEFAULT_SUPPORTED_PROTOCOLS = Arrays.asList("TLSv1.2", "TLSv1.1", "TLSv1");
+    public static final List<String> DEFAULT_SUPPORTED_PROTOCOLS = Arrays.asList("TLSv1.2", "TLSv1.1");
     public static final SSLClientAuth CLIENT_AUTH_DEFAULT = SSLClientAuth.REQUIRED;
     public static final SSLClientAuth HTTP_CLIENT_AUTH_DEFAULT = SSLClientAuth.NONE;
     public static final VerificationMode VERIFICATION_MODE_DEFAULT = VerificationMode.FULL;

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ssl/SSLConfigurationTests.java

@@ -11,6 +11,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.TestEnvironment;
 import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.xpack.core.XPackSettings;
 import org.elasticsearch.xpack.core.ssl.TrustConfig.CombiningTrustConfig;
 
 import javax.net.ssl.KeyManager;
@@ -22,6 +23,7 @@ import java.util.Arrays;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.everyItem;
+import static org.hamcrest.Matchers.hasItem;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.isIn;
@@ -35,6 +37,8 @@ public class SSLConfigurationTests extends ESTestCase {
         assertThat(globalConfig.keyConfig(), sameInstance(KeyConfig.NONE));
         assertThat(globalConfig.trustConfig(), is(not((globalConfig.keyConfig()))));
         assertThat(globalConfig.trustConfig(), instanceOf(DefaultJDKTrustConfig.class));
+        assertThat(globalConfig.supportedProtocols(), equalTo(XPackSettings.DEFAULT_SUPPORTED_PROTOCOLS));
+        assertThat(globalConfig.supportedProtocols(), not(hasItem("TLSv1")));
     }
 
     public void testThatOnlyKeystoreInSettingsSetsTruststoreSettings() {