This document discusses VoIP security threats like fraud and denial of service attacks. It provides examples of VoIP fraud causing losses of thousands of dollars or euros. It also describes common VoIP attacks like extension/password brute forcing, INVITE attacks, and exploiting default passwords. The document demonstrates using the Metasploit framework to launch SIP-based denial of service floods and discusses countermeasures like firewalls, monitoring, and session border controllers. It includes exercise notes about configuring Kamailio to defend a VoIP provider serving a lawless island from various attacks.

1. InfoSec & VoIP
Laboratorio de conmutación
Jesús Pérez Rubio
jesus.perez@quobis.com
@jesusprubio
25/09/2012
http://www.quobis.com

2. Contents
- VoIP fraud examples
- VoIP threats "in the wild"
- VoIP & DoS (flood)
- Demo: Metasploit SIPflood module
- Countermeasurements
- Exercise notes

3. VoIP fraud examples (I)
- 1 month -> 60.000 $
- 1/2 day -> 23.000 min. -> 15.000 euros
- 46 h. -> 11.000 calls -> 120.000 $
- 500.000 calls -> 1.000.000 $
...
- http://shadowcommunications.co.uk/ (Offline)
- 1.500.000 calls
- 11.000.000 euros
- 42 individuals

4. VoIP fraud examples (II)

5. VoIP threats "in the wild"
- NO eavesdropping, password cracking, etc. (this time)
-> Encryption
- Extension/password brute-force
- INVITE attack
- Default web panel passwords
- DoS/DDoS flood

6. Extension/password
brute-force (I)

7. Extension/password
brute-force (II)

8. INVITE attack
sip:+442032988741
sip:+000442032988741@XX.YY.ZZ.189
sip:1442032988742@XX.YY.ZZ.189

9. INVITE attack
sip:+442032988741
sip:+000442032988741@XX.YY.ZZ.189
sip:1442032988742@XX.YY.ZZ.189
- INVITE authentication ->
Kamailio WIN!

10. Default web panel passwords (I)

11. Default web panel passwords (II)

12. Default web panel passwords (III)

13. DoS
- DoS (Denial of service)
- Types:
- Communication interruption
- Malfomed packets (Teardrop)
- Physical destruction
- Flood
- DDoS
- Tools: LOIC, Hulk, Aircrack-ng, Exploit-DB

14. DoS (Impact)

15. VoIP & DoS
- Impact! vs. (web application)
- Application layer -> Increase performance
- SIP proxy vs. PBX
- Tools:
- Malformed packets:
- Fuzzing (Voiper)
- Flood:
- Sipvicious
- udpflood, inviteflood, rtpflood, iaxflooder
- SIPp
- Problems:
- Old
- Diversity of languages -> Complex use/customize
- Lack of report generation mechanism

16. SIPflood (REGISTER)

17. SIPflood (INVITE)

18. SIPflood_tcp (INVITE)

19. SIPflood_DDoS (INVITE)

20. Countermeasurements
- General
- Firewall
- Secure passwords
- Upgrades
- Specific:
- Monitoring
- Fail2ban
- ?¿ module (Kamailio)
- IDS/IPS (Snort/Prelude)
- Session Border Controller (SBC)

21. References
- http://blog.sipvicious.org/2010/12/11-million-euro-loss-in-voip-fraud-and.html
-http://www.securitybydefault.com/2012/03/desarrollando-para-metasploit-ii.html
- http://code.google.com/p/metasploit/source/browse/sip/sipflood.rb
- http://kb.asipto.com/kamailio:usage:k31-sip-scanning-attack
- http://saghul.net/blog/2010/06/17/deteniendo-un-sip-flood-con-opensips-y-el-
modulo-pike/
- http://www.kamailio.org/docs/modules/1.4.x/pike.html
- http://kamailio.org/docs/modules/devel/modules/pipelimit.html
- http://kamailio.org/docs/modules/1.4.x/ratelimit.html
- http://nicerosniunos.blogspot.com.es/2011/09/voip-information-gathering-metasploit.
html
- http://nicerosniunos.blogspot.com.es/2012/07/bruteforcing-sip-extensions-with.html
- http://code.google.com/p/sipvicious/w/list
- http://blog.sipvicious.org/
- http://blog.pepelux.org/2012/02/15/asterisk-invite-attack/
- http://www.hackingvoip.com/
- http://www.offensive-security.com/metasploit-unleashed/Main_Page
- http://www.securitybydefault.com/2012/09/riesgos-reales-en-voip.html
- http://www.backtrack-linux.org/

22. Exercise notes
-Option 3: you will configure Kamailio for Drake Island. This island has been a
pirate refuge for centuries. This tradition survives and nowadays this island has the
world highest cracker rate per km2. Last year we used SIPvicious toolkit to test the
security of our Kamailio server. Though simple, it’s quite powerful, hacker community
skills improve day after day so you must use more powerful tools. That’s the reason
why this year will use the Metasploit modules implemented by our colleague jesus.
perez@quobis.com to simulate DoS, DDoS and extension brute-force attacks. Your
challenge in the practice option will be implement as many attacks and security
methods as you can. The security of this operator is in your hands. The international
prefix assigned for Drake Island is: 001788[6-7]
- References
- Any usefull (not exposed) generic attack/countermeasurement
accepted
- Metasploit SIP scan module (options.rb) bug -> SIPVicious accepted
DEFENSE!! 1 attack vector -> 1 defense mechanism

23. ?
Pol. A Granxa P.260
36400 Porriño (Spain)
Tlf. +34 902 999 465
SIP://sip.quobis.com
http://www.quobis.com