Last updated: July 20, 2021
Read time: 5 Minutes
Burp Extender lets you use Burp extensions, to extend Burp's functionality using your own or third-party code. You can load and manage extensions, view details about installed extensions, install extensions from the BApp Store, view the current Burp Extender API, and configure options for how extensions are handled.
Burp extensions can customize Burp's behavior in numerous ways, such as modifying HTTP requests and responses, customizing the UI, adding custom Scanner checks, and accessing key runtime information, including the Proxy history, Target site map and Scanner issues.
For help on creating your own Burp extensions, see the main extensibility documentation.
To submit your own extension to the BApp store, follow our submission guide.
The table shows a list of any installed extensions. You can add, remove and reorder extensions using the buttons by the extensions table. Please note:
Selecting an item in the extensions table shows information about that extension in the lower panel.
The Details tab shows the following information:
The Output tab contains details of the extension's standard output stream, and the Error tab contains the same information about the standard error stream. For each stream, you can configure whether the application's output should be directed to the system console, or saved to file, or displayed in the UI. Please note:
The BApp Store contains Burp extensions that have been written by users of Burp Suite, to extend Burp's capabilities.
You can view the list of available BApps, install specific BApps, and submit user ratings for those you have installed. You can submit your own extension to the BApp store.
If you do not have Internet access from the machine that is running Burp, you can download BApp files from the BApp Store web site, and manually install them into Burp.
Some BApps are written in Python or Ruby, and require you to download Jython or JRuby, and configure Burp with the location of the relevant language interpreters. Some BApps may require a more recent version of Burp, or a different edition of Burp.
This tab contains details of the APIs that are available for creating Burp extensions. The listing shows the APIs that are available in the version of Burp that is running. Select the name of an interface from the list to show the interface code in full.
You can also use the "Save interface files" and "Save Javadoc files" buttons to save local copies of these files, for use when developing extensions.
The following settings are available:
--disable-extensions. This will prevent Burp from automatically reloading any extensions.
These settings let you configure the environment for executing extensions that are written in Java. If your extensions use any libraries, you can specify a folder from which libraries will be loaded. Burp will search this folder and any subfolders for JAR files, and will include these in the classpath of the classloader that is used to load Java extensions.
These settings let you configure the environment for executing extensions that are written in Python. To use Python extensions, you will need to download Jython, which is a Python interpreter implemented in Java. The following options are available:
sys.pathvariable with the specified location. Using this option is useful if you have created your own set of Python libraries for use in multiple separate extensions.
Note: Because of the way in which Jython dynamically generates Java classes, you may encounter memory problems if you load several different Python extensions, or if you unload and reload a Python extension multiple times. If this happens, you will see an error like:
java.lang.OutOfMemoryError: PermGen space
You can avoid this problem by configuring Java to allocate more PermGen storage, by adding a
-XX:MaxPermSize option to the command line when starting Burp. For example:
java -XX:MaxPermSize=1G -jar burp.jar
These settings let you configure the environment for executing extensions that are written in Ruby. To use Ruby extensions, you will need to download JRuby, which is a Ruby interpreter implemented in Java. Note that you can either configure the location of the JRuby JAR file here, or you can load the JAR file on startup via the Java classpath.
Note: If you load several Ruby extensions, the same issue may arise with PermGen storage as is described for the Python environment, and the issue can be resolved in the same way.