VoIP's Security Vulnerabilities

garzpacho writes "Experts predict that attacks on VoIP systems could be right around the corner, and are calling for preemptive security measures. The BusinessWeek article compares the current state of voice-over-IP to the pre-spam email era and suggests that spammers could be the first to exploit the system. From the article: 'Here's what VoIP security breaches could mean for consumers. For starters, it's a big channel for spammers. Think of the Viagra ads that flood your e-mail inboxes now. They work because the cost of e-mailing thousands of people at once is so low, only 1% to 3% or so need to respond for it to be worth it, Ingevaldson says. Comparable economics apply to VoIP calls, he says. Then there are potential phishing attacks, where fraudsters posing as banks lead consumers to fake sites. Those and other attempts at identity theft could spring up via VoIP accounts too, experts say. Imagine the messages from relatives of deposed Nigerian dictators -- only this time they're on voice mail, too.'"

Leave Grandma alone

"By the time this becomes Grandma's problem, it's too late"

Spam in her voice mail box? Yuck. My poor grandma.

Only problem is..

Think of the Viagra ads that flood your e-mail inboxes now....only this time they're on voice mail, too.

this time a sweet female voice will make me buy it... Oh Shit. Where are you taking me today?

From theoretical to real

Of course, there is a difference between potential threats and ones VoIP consumers are actually facing today. So far, much of this is theoretical--much like fears of mass viruses on mobile phones and disastrous phishing attacks over instant-message systems (see BusinessWeek.com, 1/5/06, "IM Security Is One Tough Sell"). VoIP attacks remain rare, although Gartner says Skype has made four big patches to vulnerabilities in the last 18 months.

And while it is all just theoretical, you know someone will eventually get their jollies figuring out how to hack VoIP and create a lane for spammers in the process. Going to VoIP removes a lot of the natural barriers that protect us from telemarketting calls now, and creates new vulnerabilities. There will be a lot more Caller ID spoofing; I can even conceive of someone creating malware that would be planted on your system and track the numbers you frequently call, to build spam call trees and more importantly to get ids and numbers you might trust so you would actually answer the calls. The possibilities are staggering.

Technology isn't always so great.

At lease they (engineers and techs) are thinking ahead this time. They need to head this one off at the pass. All of this new technology is great but it is also a means for the wicked to exercise thier craft. I solved the spam problem a long time ago. It's called 'delete'. If they use voice mail, then a text message with then name or number of the caller needs to be read so you can use 'delete'. Better yet, you need an option: if no caller ID - no voice mail allowed.

Anyone else see the irony...

in having a Vonage ad under an article about VOIP security risks?

I must sound like a broken record

Yet Again, I say: use public key crypto and a web-of-trust to authenticate that a call is from somebody who has a reputation to lose.

Nothing to lose? Then the call is lowest priority, probably the bit bucket unless you're expecting an unverified call, or you're just bored and feel like risking a talk with a telemarketer.

(Sorry, it's not my fault that so many current topics are related to problems that PK happens to solve. Really, I do know that there is more to life than spreading-the-gospel-of-openpgp.)

Filter unsolicited international calls

Am I correct in assuming much of this spam will originate internationally (meaning outside the US and major European countries)?

I would imagine that the "do not call" registry will still apply to VOIP and that national companies will still have to abide by it.

If this is the case, could not a VOIP inbox be set to filter unsollicited international calls to a spam-inbox?

Yes, I understand that there is still the possibility that an unsolicited, international call may be warrented for some or even many - but this seems like at least one way of combating the enevitable deluge of voice advertisement.

Turing test!

What is bad about email is that it's not always obvious to know whether some email is spam or not. And there is also the risk of phising.

Obviously it's no concern here. If they have to make it cheap, they'll use no operator and revert to pre-recorded messages. You will know right away if the person is "human" or a "recorded message"... as long as machines fail the Turing test :)

There is nothing new about it. Junk calls existed before VOIP.

Mobile networks?

Now i accept that there are security concerns regarding interception, and consequently authentication/identification/billing and a whole host of other stuff. But did the author actually read that line about spammers? Email is an inappropriate analogy - mobile phone networks are a much better guide to the kind of abuses you will see. I don't currently get voice mail messages from His Rt Hon Umbago De ConArtist (could be a good laugh though), but i do get all sorts of "would i like to change my mobile tarif" calls. Why will VoIP be different?

Not really

VoIP is more like the pre-spam IM era than the pre-spam e-mail era. And guess what. We're past the pre-spam IM era and it isn't even close to a problem. I get a spam IM about once every few months, if not rarer, and all it contains is an obfuscated link to some camgirl website or something (I haven't clicked, I'm just guessing).

VoIP, like IM, is a medium that does not lend itself to spam. What can they do, hire telemarketers? You can't very well robot a voice system. And because each system, like IM, is closed within a company, unless that company itself is spamming, they will quickly close down the accounts of anyone who spams because it's easy for them to track.

Attacks on VoIP systems?

The attack on VoIP systems started last week -- in the U.S. House of Representatives.

They've got some nerve!

and are calling for pre-emptive security measures.

Hey, you! ...Yes, you, with the fancy "pre-emptive security mesures!" DO you know where you are? This is the Internet, darnit, and we just don't do that sort of thing around here! We've got a reputation to protect, after all. Now, get outta here kid, ya bother me.

Filtering

Fortunately, VoIP is also more like e-mail than like the traditional phone system in that filtering should be a lot easier. Ever tried to get a traditional phone company to block a phone number from calling you? Some companies will charge you extra for the privilege, while others (especially cell phone companies) will refuse to do so at all. On the other hand, VoIP companies have no excuse - the request is rather obviously implementable in software, perhaps even programmable into the user's phone, and can include whitelisting as an easily-configurable method for call filtering.

(Yes, the same should be true of traditional phone service, but the old Bells have surrounded their inner workings with such a sense of mystery for decades on end that the average Joe is unlikely to realize how easily the service can be implemented.)

And I'm Okay with That

E-mail brought us basically free international communication with text and images and attachments. Having to filter spam is a very small price to pay, especially since my off the shelf bayesian filtering (combined with temporary accounts for commercial transactions) lets through one or two "maybes" a year. If I can have basically free voice/video communication around the world, I'll gladly put up with having to secure that as well. Anything off my white-list can go to the "maybe" pile and be routed to voicemail unless I feel like taking random calls. ISPs are already implementing security to prevent spoofing. And I already use voice and video communication without any problems. Really, this is a minor inconvenience that comes with a major advance.

Whitelist Only

I know wish Asterisk it should be possible to set up a database centric version of a whitelist, and only allow those calls in. All others are given infinite rings, or route-to-ex.

Maybe the time is now to start this. If they have your #, they should have your email, IM, and there should be a web address with a captcha that gives 24 hour access or something? Maybe that's what it should do instead of infinite ring, "To access my phone, please go to www.whatever.com and type in the number you are trying to dial, and follow the instructions. Thank You."

I think this is a little different

from TFA

"VoIP calls are often routed over the public Internet, and details of those transactions can be spied on by outsiders"

It compares voip to email and talks of spam and phishing. Intercepting email is not how spammers get email addresses. They get addresses posted online and lists of addresses gotten from people who have used the addresses to sign up for shit. I have an old email acct. that is loaded with spam because I have had it posted online and signed up for stuff. I also have an acct. that is only used for email to people I know and it gets no spam. Intercepting phone calls to use the info for spamming would be too much effort per spam and ruin the profitability of spamming. Spamming works when you can get a crapload of addresses and send a ton of mail dirt cheap. If spammers had to intercept emails to get addresses to build their lists I don't think it would be a problem.

All of this business about voip security may be valid for corporations but if someone wants to spend the time/effort to listen to me order a pizza they can have at it. I use an old cordless anyway so if you want to sit outside my house with a scanner you can listen too, but I really don't care. If you have nothing better to do than listen to my calls to my mother you need a life.

Algerath

Already a problem

I already have to delete 7 or 8 unsolicited vendor calls from my voicemail every day.

Those experts wouldn't happen to work for ATT...

would they?

the Nigerian phone call

Imagine the messages from relatives of deposed Nigerian dictators -- only this time they're on voice mail, too.

I'm not saying I would want hundreds of these calls, but I would love to hear at least one of them. I seem to always put a voice to these poorly-worded emails, as I sit wondering how someone could send out tens of millions of copies of a letter without having someone first proofread the text.

I guess if there's money in it, the spammer could hire a good voice to make the call that much more appealing. Would you be so quick to delete the Nigerian vmail if Derek Jacoby were reading it?

Reliability is lower too

All high-speed Internet providers that I have ever had (Comcast, Yahoo/SBC/AT&T) suffer outages periodically - say, about once every two months for several hours on the average, and this is only the outages that I know about, since I don't use my home computer all the time. Happens at work too - at one time our business DSL was out for two days (thank you "new" AT&T). The electrical power has also been out several times. At the same time I don't remember a single problem with my land line. Note that I live in the San Francisco Bay Area, so this is a relatively high-tech place.

You end up depending on both consumer-grade Internet service and electrical power, neither of which is completely reliable. Which is probably OK, esp if you have your cell phone, so I am not advocating against Vonage.

However it strikes me that people generally do not realize that the Internet connection (as the Internet itself) is not completely reliable. At a trade show a sales person was trying to convince of the benefits of their credit card authorization software, which resides on their own server and is accessible as a web service. The idea is that the consumer pays for a service (e.g. in a hair salon) in advance and then gets to use it for a period of time. Not bad stuff, actually, but that is beside the point. When I told her that I am worried about reliability in case the internet connection is down and the customer will not be able to be authorized for the service they already paid for, she looked at me silly and said: "Ihe Interned connection down ? Does that ever happen?" Duh! It happens!

e-mail is different.

E-mail can be presented in a much more convincing manner than voice mail. Spamming on VOIP would be more akin to telemarketing on traditional phones. E-mail spam is sent en masse and is impersonal.

Spam Filtering

What no one seems to have mentioned is that at least with email you can employ spam filters which do text searches and pattern matches, along with other spam-recognition techniques. It seems impossible that VoIP spam could be filtered this way, thus leading to a glut of voicemail spam which could threaten the viability of VoIP altogether, if the spammers can find a way to do it without being detected.

Voip Vs Email Spam is very different

There is a huge difference.
How much is avg email? about 1kb
How much would a prerecorded voice msg be?
You gonna need a lot of bw to send a lot of voice messages and it will take too long...
Targeted phishing could happen on the other hand.

SIP cloning, international calls, huge bills?

Spam via VoIP is an interesting thought, but how about the more immediate threat of someone, say in some remote country, cloning my SIP and using that to make a load of international phone calls? This would run up my bill very quickly, and every VoIP provider I've checked requires that the account be tied to a credit card. My guess is that if this has already happened, it's been hushed by the VoIP provider, which covered the startled customer's bill to avoid bad publicity. And if it hasn't yet happened, I expect that it will. Who will be on the hook?

Spit (Voip Spam) will never attain spam ubiquity

Yes sending millions of emails is "free", and so is making unlimited VoiP, but Voip is less unlimited than emails, here's why.

When you decide to send an email to a group of people from domains A, B and C, where you have multiple recipients in domains A, B and C you only need to send server A one copy of the message with a list of the recipients it handles. The server then spawns copies of this message to all the mailboxes. Theoretically, you only need to make as many connections are there are domains in your distribution list.
Moreover Spam scales well with bandwith. Meaning a large message will arrive faster with more bandwith, not so much with Voip where you have real-time delivery; i.e. think of Voip as a VCR vs downloading your TV shows as files.

What this means for Spit is that they need to make individual connections for each recipient (although I know of some email like systems, but that's another story). Also they need to connect with each recipient's server or terminal as long as the message is.
What this means is that twice as many recipients will cost you twice as much in time and in bandwith for your spit message.

This fondamental difference is in my opinion a deterrent for any spammer worth his salt willing to reach thousands of recipients.

Spit doesn't scale well, spammers know that and will not pursue this activity as agressively as spamming.

Cat and mouse. Not a new game.

You know folks, this isn't a completely alien concept. Why do you think residential phone subscribers can sign up for the federally enforced national "no-call list".

Just because it's a new technology doesn't mean it's a new idea. It's a shame that people completely overlook the obvious when dealing with new technologies (see Dot Com Bust [wikipedia.org].

Obviously we are aware there is a problem..Thank you TFA.. Now.. everyone run to your terminal to enterprise off the enterprising SOBs that are going to be haxoring my shiny new VoIP telephone.

The phishing threat is probably real.

The current policy at credit card companies is retarded. More than once, I've come home to an answering machine message saying "This is Discover's Anti Fraud unit. We'd like to discuss some recent activity on your card. Please call us at 1-800-555-1212". As soon as you call, they start asking for personal information. ...How the hell am I supposed to know I'm actually talking to Discover? I'd much rather have them send me to a URL (discover.com/fraud) that lists the number, since I at least have *some* indication that it's probably discover that's running discover.com.

Anyway, yeah, this policy opens the door right up to phone phishing. Thanks Discover!

Voice spam is impractical

The way SIP works makes voice spam impractical. Basically, a call is set up in two steps. 1) The calling party sends an INVITE message to your provider's PBX / main server / whatever. This would be vonage, or whoever your VOIP provider is. This 'call' connects, and an audio path is established between your provider and the calling party. From the caller's perspective, he has a live, answered, call at this point. 2) your provider sends an INVITE message to your phone. This establishes an audio path from your phone to the carrier. At this stage, the carrier either connects the two audio streams internally, or can use another pair of INVITE messages to direct the audio streams of the two phones to each other. There's no way for the calling party to identify when that second audio stream has been established; from their perspective, the call exists as soon as the provider accepts the initial INVITE message. Obviously, you could start playing audio at that stage, but there's no guarentee someone's actually on the other end of the line. If you're doing a recorded audio play, you're faced with either loosing part of the message, or playing dead air for a while. The only way around this is to dial the direct SIP extension of the customer's phone, but you need know their userext (which is different than their actual phone number) and the IP address of the user's phone, which is highly unlikely since the end user doesn't even have those bits of information (usually) Furthermore, filtering is easy. An INVITE message has to specify a valid IP for the audio stream to be set up. It's trivial to simply block INVITE's from certain IP's in software, if your carrier / phone supports that. Spoofing an IP at this stage is impossible, since that would just prevent the RTP stream from working, and it also makes it easy to figure out who's actually calling you, since you have the IP of the server the audio is coming from. (assuming your provider did the reinvite bit, which virtually all SIP implementations do) That's totally ignoring the much higher bandwidth requirements of transmitting that many audio streams and associated problems with that.

FYI - The Dept of Justice complaints are online

If you would like to better understand this case, the US Department of Justice has made the information available online:

• News release announcing the arrests [usdoj.gov]
• Complaint filed against Edwin Pena [usdoj.gov]
• Complaint filed against Robert Moore [usdoj.gov]

They do make for interesting reading and outline how Edwin Pena put his scam together.

Dan York
Best Practices Chair, VoIP Security Alliance (VOIPSA) [voipsa.org]
Producer & Co-host, Blue Box: The VoIP Security Podcast [blueboxpodcast.com]

Separating Hype From Reality

From TFA:

... but not before the problem has succeeded in wreaking havoc. It happened with e-mail and is happening now with instant messaging and mobile devices ...

From my brain:

Really? Havoc? C'mon! Yes, spam is a problem, but my email has never been close to a state of "havoc" because of it, and filters came along pretty quickly. No, they don't work as well as I would like, but they work.

From TFA:

... Here's what VoIP security breaches could mean for consumers. For starters, it's a big channel for spammers ...

From my brain:

OK, this is more of a clarification of where the threat arises. Why is a VOIP user more vulnerable to *receiving* SPIT than a non-VOIP user? According to TFA, it's the technology and economics of *making* VOIP calls that will lead to the problem. (FYI, no SPIT from VOIP yet on my two-year old Vonage account; however, I do get regular and annoying SPIT from Congresswoman Marilyn Musgrave, who I doubt is using VOIP, because it's not in the Bible.) VOIP calls can do the same damage to landline and cellular phones, can't they?

From TFA:

... Added security vulnerabilities could erode the cost savings associated with VoIP systems ...

From my brain:

The cost savings from VOIP, as with many new technologies, are savings in *marginal* costs. Security measures aren't implemented on a per-call basis, so security threats won't affect the marginal cost savings. So, unless the security threats really are grave enough to shut down VOIP systems, I don't see how they can outweigh the cost savings.

From TFA:

... And security companies such as ISS have a financial stake in companies bracing against possible threats. ISS's basic network security now includes VoIP protection. Security software mainstays Symantec (SYMC) and McAfee (MFE) are also said to be working on VoIP security products. Both companies declined to comment for this article ...

From my brain:

They have a financial stake? Really? They probably declined comment because they thought they had done more than enough by writing the article.

the beauty of VoIP..

First all those companies that charge $ for VoIP suck. I'm talking about Skype here. What is nice at this point in the evolution is how only a certain "crowd" are using Skype. This is like the crowd that built free BBSs and other early internet devices before corporate America and every moron were building sites to make a $. I talk to some girl in China for the simple reason that she likes English.. . (she works translating other languages for a company) It's cool to be able to communicate with anybody in the world so freely. -Anyway... it's a very peaceful system at present & I hope the company keeps it so. I'm sure everybody here knows about the free calling to landlines now. If you want to have some fun, go to a site like albinoblacksheep.com or a site with a Howard Stern soundboard. Call your friends house/cell phones (the number comes up 001-234-5678 on caller ID) and go to town with the sound board. -lots of laughs..

Someone tried this on me...

Then there are potential phishing attacks, where fraudsters posing as banks lead consumers to fake sites.

I don't remember this word for word, but this is the gist...

Years ago, someone called me (with an Indian accent) and told me they were from my bank, specifically from the fraud investigation unit of my bank. They told me that some suspect activity with my credit card account had been detected and asked if I had made a purchase of x dollars at y vendor. I told them that I had not, so they said that they needed to confirm that I was the rightful card holder and that my card was in my possesion. To do this, they wanted to know my personal information (name, address, DOB, mothers maiden name, etc) and the details of the card, being number, card holder name as printed on the card, expiry and the special "security" [cough cough] number on the back.

At this stage, alarm sirens suddenly became deafening in my head.

I informed this caller that I could not be sure that they are really from my bank or calling officially and that I would not provide those details to them. I told them that I would however be happy to call my bank (supposedly them) back on a number I know to be genuine and then provide the details if need be. At this stage, the fellow on the other end of the phone sounded like he was becoming annoyed. He insisted that he was from my bank and that calling back would not be required. I insisted and then asked for a call number, so that when I ring back I could get it all done as quickly as possible. He said "ahhhh... 57". I found this odd, since usually the call numbers they give were longer. So I hung up and called my bank on the regular number which I use...

Call number "57" meant nothing to them and they told me that the call numbers they provide are longer. They told me that they had no record in their system showing that they had contacted me or needed to contact me regarding possible fraudulent activity on my credit card. They also told me that there was no record of a purchase of x dollars at y vendor.

Somehow, someone got at least the following personal information about me, to attempt this attack:

What bank my credit card was with.
Card type (VISA, MCRD, AMEX, etc).
My name.
My phone number.

For me, the scariest thing about this is that that info is actually really easy to get. All I need to do is use my credit card with human interaction and at least some of those details will be divulged to a potential criminal. With a face to face transaction, the other person will at least get bank, card type, card number, my name, expiry and security code. They will possibly get much more than that, if I am expected to fill anything out for warrantee details, or marketting, etc. With over the phone purchases, the other person will at least get my card type, card number, name and expiry, which is more than enough to go on a mail order spending spree.

So, do you trust every single schmuck you have ever had to pull your credit card out for?

Now, I wonder how safe it really is for our financial institutions to be outsourcing their staff to very poor countries. It's like "here very poor person, please handle our customers and their personal and financial information while we pay you per week what our customers would get in an hour". Oh yeah, that's a great idea. Somehow I imagine all those savings gained by exploiting very poor people in other countries, will be eaten up and then some by all the added fraud which the financial institutions must eat by law when they can't catch the "criminals".

(I put criminals in quotes not because I don't consider the fraudsters to be criminals, but rather because I consider the financial companies to be the biggest criminals of all).

Actually, this could be fun

Now we will have to have awards for the best voice acting in spam VOIP messages.

Response percentages must be wrong

"Think of the Viagra ads that flood your e-mail inboxes now. They work because the cost of e-mailing thousands of people at once is so low, only 1% to 3% or so need to respond for it to be worth it, Ingevaldson says."

That's gotta be a misquote or typo, or Ingevaldson is nuts. 1% to 3% is around the accepted minimum for dead tree spam. In an interview with a professional email spammer about a year ago (yeah, I'm too lazy to look it up) she said that she could make a good profit with a 1 in 10,000 response rate! Probably helps explain why I still get penile enlargement spam even though almost everyone on the planet who'd fall for it has undoubtedly already sent in the $50 and gotten the rock and the string.

Compared to IM?

This really depends on how open it is. I mean IM spam hasn't exactly taken off like email spam and people have claimed that IM spam would've gotten really big. And voice spamming requires an actual person on the other side. If you have an automated message, you'd get hung up immediately.

Re:You can thank stupid people.

To actually fall for that Nigerian one... my God!

Stop stereotyping the Nigerians! We're taking donations to help fight the stereotyping of Nigerians ... please send donations to my paypal account : HelpTheNigerians ... or just send me your paypal id & password and I'll do the transfer for you.

Re:You can thank stupid people.

Never underestimate the power of money to overrule common sense. I saw it every day when I worked as a software engineer.

Re:You can thank stupid people.

Exactly. VoIP phone spamming won't be any different than current telemarketing. Any landline not on the DO-NOT-CALL list gets hammered with spam, despite POTS being more expensive than VoIP.

Within one week of activating a new POTS phone line, I started receiving about three or four calls per night. It got the point where I stopped answering my home phone unless I was expecting a call. I disconnected my answering machine and turned the ringer off for about a month and now the volume of calls have dropped significantly. Now, the only calls I get are from my school asking me to donate money.

Re:You can thank stupid people.

......Within one week of activating a new POTS phone line, I started receiving about three or four calls per night. It got the point where I stopped answering my home phone unless I was expecting a call. I disconnected my answering machine .....

Caller ID in combination with an old Mac Classic used as an answering machine has solved our unwanted phone call problems almost perfectly.

The Mac allows the audible, live monitoring of the first 10 seconds of any message coming in within which time we can decide to answer the phone or not. Any number we don't know or not listed is not answered live by us at all unless the caller leaves a message, which is also not answered unless we want to. A large display caller ID shows who is calling. The Mac answers all calls we don't recognize. We have not talked to a single phone solicitor in several years. Something like this should work even better for VOIP, since the computer can contain a list of callers the recipient is willing to talk to. The other calls go into the junk call bin, just as the spam junk e-mail does. The only calls that get answered live are the wanted ones. The do not call list is worthless anyway, but just as the spammers use technology, so, technology can also work against them. Fight fire with fire.

Re:You can thank stupid people.

VoIP phone spamming won't be any different than current telemarketing.

Wrong !
That's just like saying email spam won't be any different than junk mail.
VoIP spam is a nightmare in the making. A normal telemarketer needs to pay to have access to the phone network, and needs to be a business so it could be held accountable for any wrongdoings. It cannot operate from China or the long distance costs would kill it. There is only so much calls you can initiate per second from a normal telco trunk. You also need a human operator for each call, the costs per call tipically do not allow you to waste them with recorded message.
Enter VoIP Telemarketing: anonymous Viagra kings, enjoying the anonymity and low cost of the Internet calls to make billions of robot calls from zombied machines. In my opinion, it's the worst threat facing VoIP today.

Re:You can thank stupid people.

If Homer Simpson can get the AT-5000 Autodialer http://en.wikipedia.org/wiki/Professor_Frink#AT-50 00_Autodialer [wikipedia.org] for regular phones how long before we have the VOIP equivalent?