The document summarizes the $natch competition held at Positive Hack Days 2013, which aims to demonstrate typical vulnerabilities in online banking systems. The competition uses a custom-built banking system with real vulnerabilities. Participants have one day to analyze the source code and then compete live to exploit vulnerabilities and transfer money between accounts. The workshop will demonstrate vulnerabilities like cross-site scripting, SQL injection, authentication bypass, and more.

2. $NATCH
Sergey Scherbel& Yuriy Dyachenko
Positive Technologies
Positive Hack Days 2013

3. Some history
The competition took place for the first time at PHDays 2012.
$natch aims at demonstrating typical vulnerabilities of the
online bank systems.
Positive Technologies performs security tests of the online bank
systems on the regular basis. We are really into this.
The most interesting, dangerous and simply typical
vulnerabilities are integrated into PHDays iBank right away.

4. Last year results
― 9 participants
― 4 winners
― biggest prize of 3.500 roubles
― Some winners got into positive
community 
after an extremely scary
interview of course

5. PHDays iBank 2
PHDays iBank 2 is NOT a real online banking system that is
used by actual banks.
System had been developed exclusively for the PHDays 2013
competition.
PHDays iBank 2 employs typical vulnerabilities of the online
banking systems.

6. Competition rules
― 100 bank clients
― 10 participants
― 20.000 roubles of prize money
― 1 day for source code analysis
― 30 – 40 minutes of the actual competition
― a participant will get as much money as he will manage to
transfer to his or her account
― Participants can steal money from each other

7. At the workshop
― You will be able to examine each vulnerability in detail
― Exploit vulnerabilities by yourself
― Exploit vulnerabilities with tools
― All is done on a special copy of the competition system

8. Accounts
100001:PKAC1y
100002:RNrlO9
100003:Ndl1Ix
100004:hQPuJw
100005:kpgtCI

9. Authentication
Code on the image needs to be entered

10. Mobile bank authentication
The code is not needed, thus account bruteforce is possible

11. Accounts with simple passwords
100011:password
100012:phdays
100013:qwerty
100014:password
100015:123456
100016:12345
100017:11111
100018:ninja
100019:123123
100020:sex
100021:asdzxc
100022:654321
100023:iloveyou
100024:root
100025:master
100026:superman
...

12. Transaction confirmation

13. Confirmation bypass in mobile bank

14. Payment templates modification

15. Payment templates modification
A template is not checked if it is owned by the current user

16. Payment templates modification
$$

17. Payment templates modification
$$

18. Contacts import
Most online banks have a feature that allows to import/export data

19. XML External Entity
External entities loading is not disabled
http://php.net/libxml_disable_entity_loader

20. XML External Entity
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE contact [<!ENTITY x SYSTEM "php://filter/read=convert.base64-
encode/resource=logs/changePassword.log">]>
<contacts>
<contact>
<name>name</name>
<account>90107430600712500003</account>
<description>&x;</description>
</contact>
</contacts>
http://www.php.net/manual/en/wrappers.php.php

21. XML External Entity
File contents in base64

22. Debug mode

23. Thanks for your attention
Sergey Scherbel
sscherbel@ptsecurity.ru
Yuriy Dyachenko
ydyachenko@ptsecurity.ru