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Table of Contents
maxLevel3
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Disable SSL

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Info

It is necessary to disable SSL version 3 in Carbon servers because of a bug (Poodle Attack) in the SSL version 3 protocol that could expose critical data encrypted between clients and servers. The Poodle Attack makes the system vulnerable by telling the client that the server does not support the more secure TLS (Transport Layer Security) protocol, and thereby forces it to connect via SSL 3.0. The effect of this bug can be mitigated by disabling SSL version 3 protocol for your server.

Follow the steps given below to disable SSL 3.0 support on Application ServerWSO2 Carbon based servers.

  1. Open the <PRODUCT_HOME>/repository/conf/tomcat/catalina-server.xml file. 
  2. Take Make a backup of the catalina-server.xml file and stop the Carbon server.
  3. Find the Connector configuration corresponding to TLS (usually, this connector has the port set to 9443 and the sslProtocol as TLS).
    • If you are using JDK 1.6, remove the sslProtocol="TLS" attribute from the configuration and replace it with sslEnabledProtocols="TLSv1" as shown below.

      Code Block
      <Connector protocol="org.apache.coyote.http11.Http11NioProtocol"
                      port="9443"
                      bindOnInit="false"
                      sslEnabledProtocols="TLSv1"
    •  If you are using JDK 1.7, remove the sslProtocol="TLS" attribute from the above configuration and replace it with sslEnabledProtocols="TLSv1,TLSv1.1,TLSv1.2" as shown below.

      Code Block
      <Connector protocol="org.apache.coyote.http11.Http11NioProtocol"
                      port="9443"
                      bindOnInit="false"
                      sslEnabledProtocols="TLSv1,TLSv1.1,TLSv1.2" 
  4. Start the server.

    Note

    In some Carbon products, such as WSO2 ESB and WSO2 API Manager, pass-thru transports are enabled. Therefore, to disable SSL version 3 in such products, the axis2.xml file stored in the <PRODUCT_HOME>/repository/conf/axis2/ directory should also be configured

To test if SSL version 3 is disabled:

  1. Download TestSSLServer.jar from here.
  2. Execute the following command to test the transport:

    Code Block
    java -jar TestSSLServer.jar localhost 9443 
  3. The output of the command before and after disabling SSL version 3 is shown below.
    Before SSL version 3 is disabled:

    Code Block
    Supported versions: SSLv3 TLSv1.0
    Deflate compression: no
    Supported cipher suites (ORDER IS NOT SIGNIFICANT):
      SSLv3
         RSA_EXPORT_WITH_RC4_40_MD5
         RSA_WITH_RC4_128_MD5
         RSA_WITH_RC4_128_SHA
         RSA_EXPORT_WITH_DES40_CBC_SHA
         RSA_WITH_DES_CBC_SHA
         RSA_WITH_3DES_EDE_CBC_SHA
         DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
         DHE_RSA_WITH_DES_CBC_SHA
         DHE_RSA_WITH_3DES_EDE_CBC_SHA
         RSA_WITH_AES_128_CBC_SHA
         DHE_RSA_WITH_AES_128_CBC_SHA
         RSA_WITH_AES_256_CBC_SHA
         DHE_RSA_WITH_AES_256_CBC_SHA
      (TLSv1.0: idem)

    After SSL version 3 is disabled:

    Code Block
    Supported versions: TLSv1.0
    Deflate compression: no
    Supported cipher suites (ORDER IS NOT SIGNIFICANT):
      TLSv1.0
         RSA_EXPORT_WITH_RC4_40_MD5
         RSA_WITH_RC4_128_MD5
         RSA_WITH_RC4_128_SHA
         RSA_EXPORT_WITH_DES40_CBC_SHA
         RSA_WITH_DES_CBC_SHA
         RSA_WITH_3DES_EDE_CBC_SHA
         DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
         DHE_RSA_WITH_DES_CBC_SHA
         DHE_RSA_WITH_3DES_EDE_CBC_SHA
         RSA_WITH_AES_128_CBC_SHA
         DHE_RSA_WITH_AES_128_CBC_SHA
         RSA_WITH_AES_256_CBC_SHA
         DHE_RSA_WITH_AES_256_CBC_SHA

Disable weak ciphers

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A cipher is an algorithm for performing encryption or decryption. When you set the sslprotocol is set  of your server to " TLS", only the TLS and the default ciphers are enabled by default. However, note that get enabled without considering the strength of the ciphers will not be considered when they are enabled. Therefore, ciphers. This is a security risk as weak ciphers, also known as EXPORT ciphers, can make your system vulnerable to attacks such as the Logjam attack on Diffie-Hellman key exchange. The Logjam attack is also called the Man-in-the-Middle attack. It downgrades your connection's encryption to a less-secured level (e.g., 512 bit) that can be decrypted with sufficient processing power.

To prevent these types of security attacks, it is encouraged to disable the weak ciphers, you must ensure that . You can enable only the ciphers that you want your the server to support are entered for the ciphers attribute in a comma-separated list in the ciphers  attribute. Also, if you do not add this cipher attribute or keep it blank, the browser will support all the SSL ciphers by JSSE will be supported by your server, thereby enabling . This will enable the weak ciphers.

  1. Go to the catalina-server.xml file in the Open the <PRODUCT_HOME>/repository/conf/tomcat directory/tomcat/catalina-server.xml file.
  2. Take Make a backup of the the catalina-server.xml  file and stop the Carbon server (same as for disabling SSL version 3)WSO2 product server.
  3. Add the the cipher  attribute to the existing configuration in the the catalina-server.xml  file by adding the list of ciphers that you want your server to support as follows: ciphers="<cipher-name>,<cipher-name>". For example,

    Code Block
    For Tomcat version 7.0.34 and JDK version 1.7:
    ciphers="SSL_RSA_WITH_RC4_128_MD5,SSL_RSA_WITH_RC4_128_SHA,TLSSSL_DHE_RSA_WITH_AESDES_128_CBC_SHA,
             TLSSSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA,SSL_RSA_WITH_AES_128_DES_CBC_SHA,
             SSL_RSA_WITH_3DES_EDE_CBC_SHA,TLS_DHE_DSSRSA_WITH_AES_128_CBC_SHA,SSLTLS_DHE_RSA_WITH_3DESAES_EDE128_CBC_SHA,"
     
    For Tomcat version 7.0.34 and JDK version SSL_DHE1.8:
    ciphers="SSL_RSA_WITH_RC4_128_MD5,SSL_RSA_WITH_3DES_EDE_RC4_128_SHA,SSL_RSA_WITH_DES_CBC_SHA,SSL_DHE_DSSRSA_WITH_3DES_EDE_CBC_SHA,TLS_RSA_WITH_AES_128_CBC_SHA"
  4. Start the server.
  5. To verify that the configurations are all set correctly, download and run the TestSSLServer.jar.

    Code Block
    $ java -jar TestSSLServer.jar localhost 9443
  6. Note that in the output that you get, the section "Supported cipher suites" does not contain any export ciphers.

Firefox 39.0 onwards does not allow to access Web sites that support DHE with keys less than 1023 bits (not just DHE_EXPORT). 768/1024 bits are considered to be too small and vulnerable to attacks if the hacker has enough computing resources. 

Tip

Tip: To use AES-256, the Java JCE Unlimited Strength Jurisdiction Policy files need to be installed. Downloaded them from http://www.oracle.com/technetwork/java/javase/downloads/index.html.

Tip

Tip: From Java 7, you must set the jdk.certpath.disabledAlgorithms property in the <JAVA_HOME>/jre/lib/security/java.security file to jdk.certpath.disabledAlgorithms=MD2, DSA, RSA keySize < 2048. It rejects all algorithms that have key sizes less than 2048 for MD2, DSA and RSA.