Security
Use a clock synchronization service to keep system clock values as close as possible. Security processing depends on time stamp validation and having clocks out of synchronization more than five minutes can affect performance due to unnecessary re-authentication and retry processing. (http://www3.software.ibm.com/ibmdl/pub/software/dw/wes/0710_largetopologies/LargeWebSphereTopologies.pdf)
Java Security
Java security typically reduces throughput by 15-40%. However, Java Security is not a fixed cost; rather, the cost is proportional to the number of security calls. One common manifestation of this is that one application has an overhead with Java Security enabled of X%, and then another application has a much higher overhead; in most cases, this is caused by a difference in the number of calls to security between those applications, rather than a product issue. A sampling profiler such as IBM Java Health Center is usually the best way to gauge the overhead of Java Security. Use the call stack invocation paths to reduce the number of security calls if possible.
Consider disabling Java 2 security manager if you know exactly what code is put onto your server and you do not need to protect process resources. Remember that in doing so, you put your local resources at some risk. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
Java 2 security has a significant performance cost, and therefore, do not use Java 2 security unless your application really requires it. (http://www3.software.ibm.com/ibmdl/pub/software/dw/wes/0710_largetopologies/LargeWebSphereTopologies.pdf)
Single Sign On (SSO)
To configure SSO, click Security > Global security. Under Web security, click Single sign-on (SSO). SSO is only available when you configure LTPA as the authentication mechanism in the Authentication mechanisms and expiration panel. Although you can select Simple WebSphere Authentication Mechanism (SWAM) as the authentication mechanism on the Authentication mechanisms and expiration panel, SWAM is deprecated in Version 8.5 and does not support SSO. When you select SSO, a single authentication to one application server is enough to make requests to multiple application servers in the same SSO domain. Some situations exist where SSO is not desirable and you do not want to use it in those situations.
Security Attribute Propagation
Security attribute propagation: http://www-01.ibm.com/support/knowledgecenter/SSAW57_8.5.5/com.ibm.websphere.nd.multiplatform.doc/ae/csec_secattributeprop.html
The following two custom properties might help to improve performance when security attribute propagation is enabled:
- com.ibm.CSI.propagateFirstCallerOnly: The default value of this property is true. When this custom property is set to true the first caller in the propagation token that stays on the thread is logged when security attribute propagation is enabled. When this property is set to false, all of the caller switches are logged, which can affect performance.
- com.ibm.CSI.disablePropagationCallerList: When this custom property is set to true the ability to add a caller or host list in the propagation token is completely disabled. This function is beneficial when the caller or host list in the propagation token is not needed in the environment.
Horizontal Security Attribute Propagation
The SSO option will first check the local JVM's AuthCache. This is a "use based" cache in the Java heap of the JVM. A Subject used often can remain here until the LtpaToken expiration. Next, if security attribute propagation and Dynacache are enabled, WAS will check the ws/WSSecureMap DistributedMap. If the subject is not found here, WAS will try to make an MBean call back to the server that originally created the subject. The originating server's host:port is found in the SSO token. There is a timeout value that can be set to manage this condition: com.ibm.websphere.security.tokenFromMBeanSoapTimeout. You can also disable the mbean callback: com.ibm.websphere.security.disableGetTokenFromMBean. These properties were added at 7.0.0.17, PM28382.
When front-end servers are configured and in the same data replication service (DRS) replication domain, the application server automatically propagates the serialized information to all of the servers within the same domain [using ws/WSSecureMap].
The WSSecureMap security cache settings can be adjusted through custom properties in the administrative console.
- com.ibm.ws.security.WSSecureMapInitAtStartup=true
- com.ibm.ws.security.WSSecureMapSize (integer of 100 or greater).
In some cases, having [Web Inbound Security Attribute Propagation option on the Single sign-on (SSO) panel] enabled can improve performance. This improvement is most likely for higher volume cases where a considerable number of user registry calls reduces performance. In other cases, having the feature disabled can improve performance. This improvement is most likely when the user registry calls do not take considerable resources.
You must determine whether enabling this option improves or degrades the performance of your system. While the option prevents some remote user registry calls, the deserialization and decryption of some tokens might impact performance. In some cases propagation is faster, especially if your user registry is the bottleneck of your topology. It is recommended that you measure the performance of your environment both by using and not using this option. When you test the performance, it is recommended that you test in the operating environment of the typical production environment with the typical number of unique users accessing the system simultaneously.
Note: Security attribute propagation may be set at multiple levels: cell, server, and security domain. For security domains, the option is set as a custom property with the name com.ibm.ws.security.webInboundPropagationEnabled and a value of true or false.
Explicit invalidations for ws/WSSecureMap are sent out on user logout. To disable this: com.ibm.websphere.security.web.removeCacheOnFormLogout=false
LDAP Authentication
Consider the following steps to tune Lightweight Directory Access Protocol (LDAP) authentication.
- In the administration console, click Security > Global security.
- Under User account repository, click the Available realm definitions drop-down list, select Standalone LDAP registry and click Configure.
- Select the Ignore case for authorization option in the stand-alone LDAP registry configuration, when case-sensitivity is not important.
- Select the Reuse connection option.
- Use the cache features that your LDAP server supports.
- Choose either the IBM Tivoli® Directory Server or SecureWay directory type, if you are using an IBM Tivoli Directory Server. The IBM Tivoli Directory Server yields improved performance because it is programmed to use the new group membership attributes to improve group membership searches. However, authorization must be case insensitive to use IBM Tivoli Directory Server.
- Choose either iPlanet Directory Server (also known as Sun ONE) or Netscape as the directory if you are an iPlanet Directory user. Using the iPlanet Directory Server directory can increase performance in group membership lookup. However, use Role only for group mechanisms.
Tune the connection and context pools: http://www-01.ibm.com/support/knowledgecenter/SSAW57_8.5.5/com.ibm.websphere.wim.doc/tuningtheaccesstotheldapserver.html
Tune the virtual member manager (VMM): http://www-01.ibm.com/support/knowledgecenter/SSAW57_8.5.5/com.ibm.websphere.wim.doc/tuning.html
Secure Sockets Layer (SSL), Transport Layer Security (TLS)
In some cases, using the unrestricted Java Cryptography Extension (JCE) policy file can improve performance. Refer to the information about tuning Web Services Security.
Consider using Secure Sockets Layer (SSL) client certificates instead of a user ID and password to authenticate Java clients. Because you are already making the SSL connection, using mutual authentication adds little overhead while it removes the service context that contains the user ID and password completely.
If you send a large amount of data that is not very security sensitive, reduce the strength of your ciphers. The more data you have to bulk encrypt and the stronger the cipher, the longer this action takes. If the data is not sensitive, do not waste your processing with 128-bit ciphers.
Consider putting only an asterisk (*) in the trusted server ID list (meaning trust all servers) when you use identity assertion for downstream delegation. Use SSL mutual authentication between servers to provide this trust. Adding this extra step in the SSL handshake performs better than having to fully authenticate the upstream server and check the trusted list. When an asterisk (*) is used, the identity token is trusted. The SSL connection trusts the server through client certificate authentication.
When an SSL connection is established, an SSL handshake occurs. Once a connection is made, SSL performs bulk encryption and decryption for each read-write. The performance cost of an SSL handshake is much larger than that of bulk encryption and decryption.
To enhance SSL performance, decrease the number of individual SSL connections and handshakes.
Verify that the maximum number of keep alives are, at minimum, as large as the maximum number of requests per thread of the web server (or maximum number of processes for IBM® HTTP Server on UNIX). Make sure that the web server plug-in is capable of obtaining a keep alive connection for every possible concurrent connection to the application server. Otherwise, the application server closes the connection once a single request is processed. Also, the maximum number of threads in the web container thread pool should be larger than the maximum number of keep alives, to prevent the keep alive connections from consuming the web container threads.
Increase the maximum number of requests per keep alive connection. The default value is 100, which means the application server closes the connection from the plug-in following 100 requests. The plug-in then has to open a new connection. The purpose of this parameter is to prevent denial of service attacks when connecting to the application server and preventing continuous send requests to tie up threads in the application server.
The performance of a cipher suite is different with software and hardware. Just because a cipher suite performs better in software does not mean a cipher suite will perform better with hardware. Some algorithms are typically inefficient in hardware, for example, Data Encryption Standard (DES) and triple-strength DES (3DES); however, specialized hardware can provide efficient implementations of these same algorithms.
The Message Digest Algorithm (MD5) and Secure Hash Algorithm (SHA) are the two hash algorithms used to provide data integrity. MD5 is generally faster than SHA, however, SHA is more secure than MD5.
Data Encryption Standard (DES) and Rivest Cipher 2 (RC2) are slower than Rivest Cipher 4 (RC4). Triple DES is the most secure, but the performance cost is high when using only software.
The cipher suite providing the best performance while still providing privacy is SSL_RSA_WITH_RC4_128_MD5. Even though SSL_RSA_EXPORT_WITH_RC4_40_MD5 is cryptographically weaker than RSA_WITH_RC4_128_MD5, the performance for bulk encryption is the same. Therefore, as long as the SSL connection is a long-running connection, the difference in the performance of high and medium security levels is negligible. It is recommended that a security level of high be used, instead of medium, for all components participating in communication only among WebSphere Application Server products. Make sure that the connections are long running connections.
Use certificates that are signed by a certificate authority (CA), preferably an internal CA for internal communications, whenever possible. This usage reduces the number of signers that are needed in a truststore and allows the replacement of a personal certificate without ramifications to clients.
You can use SSL offload devices to reduce the SSL overhead for internet and intranet facing applications. Using keepAlive, which is on by default, dramatically minimizes the SSL overhead, removing the SSL handshakes, which tends to be the largest overhead of SSL.
J2C Authentication Subjects
Read-only Subject enables a new cache for J2C Auth Subjects when using container-managed auth data aliases. If the J2C auth subject does not need to be modified after it is created, the following new tuning parameters can be used to improve Java 2 Security performance:
- com.ibm.websphere.security.auth.j2c.cacheReadOnlyAuthDataSubjects=true
- com.ibm.websphere.security.auth.j2c.readOnlyAuthDataSubjectCacheSize=50 (This is the maximum number of subjects in the hashtable of the cache. Once the cache reaches this size, some of the entries are purged. For better performance, this size should be equal to the number of unique subjects (cache based on uniqueness of user principal + auth data alias + managed connection factory instance) when role-based security and Java 2 security are used together).
Authentication Cache
Consider increasing the cache and token timeout if you feel your environment is secure enough. By increasing these values, you have to re-authenticate less often. This action supports subsequent requests to reuse the credentials that already are created. The downside of increasing the token timeout is the exposure of having a token hacked and providing the hacker more time to hack into the system before the token expires. You can use security cache properties to determine the initial size of the primary and secondary hashtable caches, which affect the frequency of rehashing and the distribution of the hash algorithms. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
CSIv2 Cache
Ensure that stateful sessions are enabled for CSIv2. This is the default, but requires authentication only on the first request and on any subsequent token expirations.
Consider changing the values for the CSIv2 session cache. Changing these values can avoid resource shortages. Refer to the Common Secure Interoperability Version 2 outbound communications topic for more information.
If you are communicating only with WebSphere Application Server Version 5 or higher servers, make the Active Authentication Protocol CSI, instead of CSI and SAS. This action removes an interceptor invocation for every request on both the client and server sides.
User Authorization
Map your users to groups in the user registry. Associate the groups with your Java Platform, Enterprise Edition (Java EE) roles. This association greatly improves performance when the number of users increases. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
Servlet Security Constraints
Judiciously assign security-constraints for servlets. For example, you can use the *.jsp URL pattern to apply the same authentication data constraints to indicate all JavaServer Pages (JSP) files. For a given URL, the exact match in the deployment descriptor takes precedence over the longest path match. Use the *.jsp, *.do, *.html extension match if no exact matches exist and longest path matches exist for a given URL in the security constraints. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
EJB Method Permissions
Judiciously assign method-permissions for enterprise beans. For example, you can use an asterisk (*) to indicate all the methods in the method-name element. When all the methods in enterprise beans require the same permission, use an asterisk (*) for the method-name to indicate all methods. This indication reduces the size of deployment descriptors and reduces the memory that is required to load the deployment descriptor. It also reduces the search time during method-permission match for the enterprise beans method. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
Administrative Security
Consider changing your administrative connector from Simple Object Access Protocol (SOAP) to Remote Method Invocation (RMI) because RMI uses stateful connections while SOAP is completely stateless. Run a benchmark to determine if the performance is improved in your environment. (http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/topic/com.ibm.websphere.nd.multiplatform.doc/ae/tsec_tune.html)
If WebSphere Application Server security is used only to protect administrative access, disable application security so that the collaborators do not perform actions that might affect throughput. (http://www3.software.ibm.com/ibmdl/pub/software/dw/wes/0710_largetopologies/LargeWebSphereTopologies.pdf)
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