Java(Servlet) Dangerous function

<—————-Directory Traversal————→

• Open a file
  File f = new File(“filePath”, userinput);

• Reading & Writing file
  java.io.FileInputStream
  java.io.FileOutputStream
  java.io.FileReader
  java.io.FileWriter

Ex: FileInputStream fis = new FileInputStream(“filePath” + userinput);

<—————-SSRF————→

• Open a URL
  InputStream in = new URL.openStream()
  where url = User supplied Input