Modifying and Building Burp Extensions Quick Reference

ModifyAndBuildingBurpExtensions.md

Quick Reference

This section is a boiled down version of everything above. It should serve as an easy reference. These steps assume you've identified and installed the correct JDK.

Modify and Re-Jar Extension

1. Locate the jar file: Extender > Extensions > Select extension > Details. bapps\ directory is located at C:\Users\yourusername\AppData\Roaming\BurpSuite\bapps
2. Backup the original jar file to a different folder, outside of bapps.
3. Change extension from .jar to .zip, extract contents, delete .zip file
4. Make your modifications
5. Re-jar: jar cvf yourJarName.jar -C extractedContentsDirectory/ .
6. Reload extension in Burp: Extender > Extensions, uncheck Load and check it again

Compile Extension from Source

1. Clone or download extension source code
2. Make your modifications, and create build location
3. Compile source code: javac -cp "C:\Program Files\BurpSuitePro\burpsuite_pro.jar" -d buildLocation sourceCodeLocation\*.java
4. Create Jar: jar cvf yourJarName.jar buildLocation/*.class anyOtherDependencies1 anyOtherDependencies2
5. Load Jar into Burp: Extender > Extensions, Add, Extension type Java and locate built jar, Next, Close
6. Disable original version of extension from BApp store

For the Compile Extension from Source

Make sure you run the jar cvf command from within the buildLocation to avoid the java.lang.ClassNotFoundException: burp.BurpExtender error as detailed here https://www.vanstechelman.eu/content/solution-javalangclassnotfoundexception-when-loading-your-burp-suite-extention