Customizing Error Pages¶
WSO2 products display errors, exceptions, and HTTP status codes in full detail. These are known as Verbose error messages. These error messages contain technical details such as stack traces. There may also disclose other sensitive details. Attackers may fingerprint the server, based on the information disclosed in error messages. Alternatively, attackers may attempt to trigger specific error messages to obtain technical information about the server. You can avoid these situations by configuring the server to display generic, non-detailed error messages in Apache Tomcat.
The pages that should be displayed on a
certain throwable exception, error, or an HTTP status code are specified
in the <CARBON_HOME>repository/conf/tomcat/carbon/WEB-INF/web.xml
file. You can customize those error pages as preferred. For example,
if you try to access a resource that is not available in the product
server (e.g., https://10.100.5.72:9443/abc ), you will view the error
page as follows: Error 404 - Not Found
.
You can customize the above error message by following the instructions given below.
-
Create a directory named
resources
inside theMI_HOME/src/main/
directory, and then create another directory namedweb
inside it.Info
MI_HOME
denotes the top-level directory of your Maven project. -
Create a new HTML error page (e.g.
new_error_404.html
file) as shown below. This contains the customized error page.<html> <head> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> <title>404 - Error not found</title> </head> <body> <h1>Sorry, this resource is not found.</h1> </body> </html>
-
Add the
new_error_404.html
file inside theMI_HOME/src/main/web
directory. -
Add the following property below the
<version>
element in the<PROJECT_HOME>/pom.
xml file:<packaging>bundle</packaging>
-
Add the following configurations inside the
<plugins>
element in theMI_HOME/pom.
xml file.<plugin> <groupId>org.apache.felix</groupId> <artifactId>maven-bundle-plugin</artifactId> <extensions>true</extensions> <configuration> <instructions> <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName> <Bundle-Name>${project.artifactId}</Bundle-Name> <Import-Package> org.osgi.framework, org.osgi.service.http, org.wso2.carbon.ui, javax.servlet.*;version="2.4.0", *;resolution:=optional </Import-Package> <Fragment-Host>org.wso2.carbon.ui</Fragment-Host> <Carbon-Component>UIBundle</Carbon-Component> </instructions> </configuration> </plugin>
-
Add the following configurations inside the
<dependencies>
element in theMI_HOME/pom.
xml file:<dependency> <groupId>org.apache.felix</groupId> <artifactId>org.apache.felix.framework</artifactId> <version>1.0.3</version> </dependency>
-
Build the Maven project by executing the following command:
mvn clean install
-
Once the project is built, copy the JAR file (from the
MI_HOME/target/
directory) to theMI_HOME/repository/components/dropins/
directory. -
Change the following configurations in the
MI_HOME/repository/conf/tomcat/carbon/WEB-INF/web.xml
file.<error-page> <error-code>404</error-code> <location>/carbon/new_error_404.html</location> </error-page>
Tip
You need to replicate this configuration, and change the values of the
<error-code>
and<location>
elements accordingly for each new HTML error page you add. -
Restart the product server.
- Access the following URL again, to test the error page you customized: https://10.100.5.72:9443/abc.
You will view the new error page with the following content: "Sorry, this resource is not found.
"