Despite the fact that I was an impressionable young college student during the height of the punk rock movement, I was never much of a fan of the genre. While I enjoyed a few songs by the Clash and some of the more obscure punk bands like Eddie and the Hot Rods (yes, they were a real group), I preferred a less chaotic sound.
Of all the punk bands that were popular with my university peers, the one that I could never stand was the Sex Pistols. While I have no problem with loud, they were just plain noisy. Their lead singer was a bloke that went by the name of Johnny Rotten. He was out-of-tune, out-of-time, and just plain, well, rotten.
Alongside Mr. Rotten was the band’s bass player, Sid Vicious. However, Sid is possibly more famous for killing his girlfriend, Nancy, than for any music he might have made in his short life.
So, what does this have to do with unified communications? Well, it just so happens that the most popular SIP “hacker” tools goes by the name of SIPVicious and despite its reference to a heroin addicted murderer, you will want to throw this one on the turntable and give it a spin.
SIP Vicious
SIPVicious is a collection of freeware tools that can be used to test many of the vulnerabilities of your SIP platform. Specifically, it consists of these modules:
- svmap – This is a sip scanner. It lists SIP devices found within an IP range.
- svwar – This module identifies active extensions on a PBX.
- svcrack – This is an online password cracker for a SIP PBX.
- svreport – This module manages sessions and exports reports in various formats.
- svcrash – This module attempts to stop unauthorized svwar and svcrack scans.
Of these, allow me to spend a little time on svcrack.
Weak telephone passwords are a direct path to toll fraud. This table shows you the maximum time it would take a hacker to break into an unprotected system.
- A 4-digit pin (0000-9999) can be hacked in 142 seconds.
- A 5-digit pin (00000-99999) can be hacked in 8 minutes.
- A 6-digit pin (000000-999999 can be hacked in 9 hours.
- A 7-digit pin (0000000-9999999) can be hacked in 6 days.
- An 8-digit pin (00000000-99999999) can be hacked in 3 weeks.
By running svcrack against a system that uses 4-digit telephone pins, a 14-year-old kid can register a SIP device in two minutes or less. Of course, it probably won’t be a 14-year-old kid, but someone who is in the business of stealing long distance minutes from unsuspecting companies. I’ll let you do the math to figure out how long it takes to rack up a $10,000 bill for calls to Colombia.
Now, just because the bad guys use SIPVicious, don’t think that you can’t do the same. SIP Vicious is freeware so there is nothing stopping you from downloading your own copy and exercising the security aspects of your system. Don’t limit yourself to svcrack, though. Play with all the different components to determine how they impact your SIP solution. Believe me, the hackers will be doing that without your knowledge or permission.
Note: SIPVicious is a collection of Python scripts. If you haven’t already done so, you will need to download and install Python.
An example svcrack invocation will look similar to this:
svcrack.py -u 3000 -d passwords.txt 10.11.230.49
3000 is the extension you want to register against, passwords.txt contains the passwords you want to attempt, and 10.11.230.49 is the IP address of the SIP server you want to break into.
The script will cycle through all the entries in the passwords file until it runs out of passwords or bingo, the REGISTER succeeds.
Take Control of Your Destiny
There is nothing stopping you from implementing strong protection to prevent those SIP Vicious attacks from doing any harm. Here a a few easy steps that any enterprise can take.
- Increase the number of digits used for your telephone passwords. I strongly suggest that you get your users accustomed to nothing less than 8-digits. That’s the number I use on my SIP devices today.
- Follow best practices for those passwords. Although you are limited in what you can do with digit-only passwords, implement software that ages those passwords and prevents users from reusing the same ones over and over again.
- Ingress and egress all your remote traffic through a session border controller (SBC). Make sure that your SBC is one that recognizes SIP Vicious and can neutralize malicious registration attacks.
- Configure Session Manager firewall policies to rate limit the number of registration attempts that a SIP user agent can send within a given time period. Be careful that any policy you set does not preclude an SBC from propagating REGISTER requests from remote clients.
Mischief Managed
It is essential that you identify and mitigate threats before you are hit with toll fraud or the theft of your valuable communications data. SIPVicious is a set of tools that can cause great harm as well as help you secure your SIP platform. Thankfully, you have the opportunity to choose how they will be applied to your SIP platform.
There are other SIP hacking tools out there (e.g. Sippts) and I highly recommend that you take the time to explore them, as well. The goal is for you to try them out on your platform before the hackers do. Believe me, they are not going to wait for your permission to attack. Beating them at their own game may save you money, time, and grief.