XSS (Cross Site Scripting)

• The following is done using the Ubuntu804Server_xsssi Virtual Machine found in the usual place. cd /virtual mkdir /virtual/$USER cd /virtual/$USER scp $USER@dh2020pc01.utm.utoronto.ca:/virtual/arnold/Ubuntu804Server_xsssi.zip . unzip Ubuntu804Server_xsssi.zip vmplayer & # Choose I Moved It

  Once you download and start the VM, it should tell you its IP address. Using this, you should be able to launch a browser on the host machine and connect to the guest webserver. The important URL is (assuming you have inet addr:10.10.10.129 as an IP address)

  http://10.10.10.129/xss Note: If the network does not come up, try login as arnold/password sudo bash ifdown eth0 ifup eth0 ifconfig # should show 10.10.10.129 now
• Run through the examples, understanding the vulnerabilities both from the outside and from the inside. Run each of the exploits, understanding what they are doing.
• Login to the server (you should be able to ssh into the server, if you like). Use arnold/password. Then sudo bash, entering password again. You can now take a look at the scripts in /var/www/xss in particular
  • xssEcho.php
  • xssAddString.php
  • xssShowStrings.php
• Now fix the above scripts to eliminate the XSS vulnerability. Take a look at the OWASP XSS Prevention Cheat Sheet and this, so basically, use htmlentities in php, or whitelist.
• Show Jai (your TA) that you have fixed the XSS vulnerability in the above scripts.