How to reveal blocked caller ID info: a video guide to risky behavior

Let's say for some reason someone has his or her caller ID blocked and is calling you all the time. Let's then say you really want to know who that person is for, you know, whatever reason -- not that we'd know anything about that. Some crafty phreaker types have come up with a way to do this using an enterprise-spec asterisk box and a SIP trunk provider. In a demonstration video, a hacker tweaks said asterisk box with some new configurations to strip out privacy flags, forward the call to another number, and ultimately reveal caller ID information which, surprisingly, is still available. This isn't meant to be easy, but if the terms "prepend," "SIP trunk," and "asterisk box" don't scare you away, go ahead and watch the video after the break. Big disclaimer: we're not responsible for your broken gear, jail time, or restraining orders.

[Seanross @ Jul 21st 2008 10:09AM]

Tag, wanna check this out later. sounds cool

[konshuss @ Jul 21st 2008 1:32PM]

is this what you do instead of bookmarking?

[hiimcliff @ Jul 21st 2008 9:35PM]

LOL @ you looking like nick cannon

[Seanross @ Jul 22nd 2008 5:46AM]

What in the world is wrong with tagging this, why clutter up my bookmarks?
Its not like I said first or something...

[neofolklore @ Jul 22nd 2008 8:12AM]

bookmarks are a thing of the past. everytime you upgrade or format your computer after carefully backing things up, its OOPS lost my bookmarks.

del.icio.us and tags are in.

[konshuss @ Jul 22nd 2008 11:18AM]

no no, what's in is the kind of logic that would also see someone who writes random nonsense into the comments of a webpage as a means of saving it as someone who would probably call your phone up just to tell you they want to talk to you some other time.

[OneLove @ Jul 21st 2008 10:19AM]

"This isn't mean to be easy"

[OneLove @ Jul 21st 2008 10:24AM]

This article makes me feel old. (Thanks engadget).

[Miike @ Jul 21st 2008 10:24AM]

Think I'll just stick to the old "Hello?... Who's calling?" hack.

[From My Cube @ Jul 21st 2008 10:25AM]

hello neo

[neofolklore @ Jul 22nd 2008 8:13AM]

hiiii

[Rob @ Jul 21st 2008 10:26AM]

This kid sounds like Wyatt in "Weird Science."

[Dave P @ Jul 21st 2008 6:04PM]

HAHAHAHAHAHAHA nail on the head! Good call.

[Prasand J. @ Jul 21st 2008 10:37AM]

I'm kinda torn about this.

On one hand, part of me wants to do it cause private calls are annoying (then others with private numbers forget to unblock their number). But on the other hand, if all numbers are unblocked ... it'll cause me to answer the phone more often, even when I don't know a number.

Ehhh, I'll probably do it and just not answer numbers I don't know.

I wonder how long it'll take before the services prevent it from being used in such a manner.

*shrugs*

[Dave Bergschneider @ Jul 21st 2008 10:41AM]

This is interesting. Truth be told, I'm not entirely sure why anyone uses private settings because that is what telemarketers do and they get blocked for it.

[Dave Bergschneider @ Jul 21st 2008 10:43AM]

I don't know why people even block their numbers anymore. I always pickup & hang up on them because it is likely spam callers.

[Robert Abramson @ Jul 21st 2008 4:43PM]

A lot of law enforcement employees/agents use it, as well as just about anyone whose identity is valuable. A lot of criminals get out of jail ten years later and want to harm the people who put them there; prosecutors and police as much as witnesses.

[r3loaded @ Jul 21st 2008 1:42PM]

We had this "feature" on our Vonage connection to block private numbers. The telemarketing calls stopped instantly, but this was also blocking some international calls from relatives as their phone company didn't forward their number for whatever reason.

Let's just say my aunts and uncles weren't pleased that they couldn't phone us for 2 months straight..

[Mach @ Jul 21st 2008 10:48AM]

Yes, finally a good quality article off engadget, aside from all that iphone crap

[lance @ Jul 21st 2008 11:34AM]

you just had to say the i word didn't you.

[Mach @ Jul 21st 2008 12:40PM]

yes, douchebag

[RedBull Runner @ Jul 21st 2008 3:56PM]

Just to make Mach happy, ITT:

Discuss how to do it with an iPhone.

Of course you can use the iPhone ssh client to set it up on a different system... but i want asterisk on the iPhone. or at least a SIP client

[Ed @ Jul 24th 2008 7:36PM]

Maybe this guy can make it happen...
http://www.mgamble.ca/blog/category/iphone-asterisk-port/

[MadMike @ Jul 21st 2008 11:01AM]

Kevin Mitnick using an iPhone. Never saw that coming. FBI finally let him out of prison though. After they found like 10Gb of credit info on his PC, they held him without trial for years. Of course after they let him out, he dropped off the face of the earth. He could have sued the government, even though he got mostly time already served because it took them like 4 years to charge him with a crime. That's still unconstitutional.

If you had a VoIP system at home, you could have it send you extra information about the caller with reverse phone directory info. Write an app for the iphone that will accept the extra data through the internet and display it when the call is received.

It's expensive, but it would work and be really convenient.

[MadMike @ Jul 21st 2008 11:05AM]

Just Wikipedia'd him. They said he CC stuff was a myth and it was actually pirated software. Odd. Because I was almost certain the NYT said it was credit info.

[Benson @ Jul 21st 2008 7:22PM]

So you're saying you read it in the NYT, and it's a myth, and... you're surprised?

[retro77 @ Jul 25th 2008 7:32PM]

Na, 'ol Kevin runs his own security consulting business making tons of money.

[Kurian @ Jul 21st 2008 11:06AM]

In Soviet Russia, Caller ID blocks you.

[Jonathan @ Jul 21st 2008 11:21AM]

Anyone realized that this is by THE Kevin Mitnick?

That guy also did all this:

* Using the Los Angeles bus transfer system to get free rides[2]
* Evading the FBI[3]
* Hacking into DEC system(s) to view VMS source code (DEC reportedly spent $160,000 in cleanup costs)[3][2]
* Gaining full admin privileges to an IBM minicomputer at the Computer Learning Center in LA[2]
* Hacking Motorola, NEC, Nokia, Sun Microsystems and Fujitsu Siemens systems[3]
* Wiretapped FBI agents[4]


http://en.wikipedia.org/wiki/Kevin_Mitnick

[michael @ Jul 21st 2008 11:23AM]

Grandcentral.com, a google service, adds call screening of the form:

"Who shall I say is calling" to every call. No more blocked callers.

[Ray Reece @ Jul 21st 2008 12:55PM]

I second the GrandCentral comment.
You can also get unlimited free phone calls by using a calling plan with those "call any X amount of people for free" features in conjunction with GrandCentral ^_^

-Ray

[Just-uh-Thought @ Jul 28th 2008 6:16PM]

Amen to the GrandCentral Comment as well.

When I switched carriers two weeks ago I decided that I never wanted anyone to have my real number due to it being a cell (had bad experience with telemarketers calling it continuously and wrong numbers) I gave everyone my GrandCentral number and uploaded my phonebook to GrandCentral. Now, anyone calling me that isn't in my Phonebook gets ONLY voicemail stating that they MUST leave a number for me to call them back if they wish to call me, family and friends ring My phone - or my Father's house depending on relationship and/or time of day. Wonderful service and I am totally glad that Google bought the original company thus I am in beta for an otherwise pay-service!

[thedesolate1 @ Jul 21st 2008 11:26AM]

Good now i can track down that whore who stalks me at 12 am every night....

[Michael @ Jul 21st 2008 11:36AM]

I have Vonage set to reject anonymous called automatically. What I would like to see is a way to find the real number for people that are spoofing Caller ID tags. I get calls from telemarketers at [phone] or 39-484. Since they are going through the trouble of being all sneaky, I'd love to be able to catch them, or better yet, look them up so I can mess with them. i.e. place ads with their corporate number on Craigslist for Free Gas or something. ;)

[joe blow @ Jul 21st 2008 12:10PM]

Hmm, who would be stalking a nerd who could pull this off anyway?

[DYLAN C @ Jul 21st 2008 12:14PM]

Kevin Mitnick....boy, he sure does love telephone h4x1ng.

[Quicksilver4648 @ Jul 21st 2008 12:18PM]

Personally, if their ID is blocked I don't answer. They can leave a message. If they don't want me knowing who they are then I assume they wont be mad when I don't answer.

[CraigJ @ Jul 24th 2008 6:40PM]

It's still a problem if your phone rings a couple of times at 1AM Monday morning.

[OX4 @ Jul 21st 2008 12:30PM]

I'm guessing that the only people that could actually get this working are the type of people that get no phone calls from anyone.

[Zapharus @ Jul 21st 2008 12:57PM]

I have an iPhone (first-gen) and I came across something odd about a month ago. The admissions counselor from my school called me from her home number and left a voice-mail. In my missed call log it clearly showed it as a blocked number but in my voice-mail queue it showed the actual number. After listening to the message I called her back and she was shocked and asked how I got her number since it's a blocked number, I simply told her that it showed up on my caller ID - it would have been difficult explaining visual voice-mail to someone who's never owned an iPhone. I don't know if AT&T dropped the ball there of if this was just some random glitch but after reading this post I'm gonna have people I know who have a blocked ID and have them call & leave a message to see if it happens again.

[William C Bonner @ Jul 21st 2008 12:59PM]

The screwy thing is that CallerID is purely a consumer service on analog telephone lines. It's different from the various other accounting numbers that are transferred with every call configuration for billing purposes. (ANI is one of the real numbers if I remember correctly)

Way back when I had an ISDN line and callerid was relatively new, and not allowed in california for privacy reasons, I learned quite a bit for a layman about SS7 and what was possible. If you are receiving on an 800 number, the information is delivered to you so that you can keep track of all of your costs.

Since most cell phones only get a number delivered digitally, I'd be interested in knowing what that number matches up to? Perhaps it's the call billing number?

[Rajesh @ Jul 21st 2008 1:14PM]

Simple solution for all:
If you want to call back blocked caller, you can simply dial *69 (it will cost you money) but it will call back blocked number without you knowing their caller id.


Technical details about caller id:

When a call is delivered from one exchange to the other exchange, it typically carries calling number (with privacy flag), calling name (with separate privacy flag), called number and billing number.

Some times calling name is obtained by the final exchange by doing a database look up. When the call is delivered to your analog phone (or any subscriber phone e.g. cell phone or voip phone), typically information delivered in caller id is caller name and number, if name OR number is private, special string is delivered instead of name or number to denote Private or Unavailable.

Typically end equipments do not get blocked caller id information (in analog world there is no way to deliver a number and say blocked at the same time).

So only way to tap onto this information is if you have VOIP trunk or have your call forwarded to a voip trunk. Now if you own the VOIP trunk you can sniff this information (if not encrypted) or change program to print it anyway you want.

Not a big deal at all.

[Phone geek @ Jul 26th 2008 12:25AM]

William -

You need to go back and study your ss7. You are horribly misinformed.

Caller ID is not analog and it requires digital trunks with SS7 between the class 5/4 offices before it works.

ISUP = ISDN User Part and may be the message you are referring to.

Wireless providers in the US peer to tandems with ISUP trunks.

Google ANSI - ss7 Initial Address Message (IAM)

[Mac @ Jul 28th 2008 12:54PM]

William --

I have a Palm Centro phone that is receiving Restricted Caller ID calls. I am certain who the caller is, as I am under an Emergency Protective Order from a felony stalker. It seems that things are gearing up again and before some bunny gets boiled on my stove, I want to be able to give the police the info they need to bring the stalker back to jail. They won't do it on their own, which sucks. I am fairly techno-savvy, but the terms "prepend," "SIP trunk" and "asterisk box" DO scare me. Is there a way I can do this on my cell phone and Mac?

[Ethan @ Jul 21st 2008 1:09PM]

She's in Georgia! Thanks!

[Harry Wagstaff @ Jul 21st 2008 1:50PM]

And by Georgia you mean Pallet Town, right?
Orig series ftw.

[Fruition @ Jul 21st 2008 1:53PM]

O_O

[AJ @ Jul 21st 2008 2:42PM]

does this work for text messages? i get a lot of *67 texts..

[Spektor @ Jul 21st 2008 4:10PM]

If you do not want your phone number to be revealed, there is a service called Safercalls. I've personally used this service to call toll-free numbers. (creditors) I believe you can also forward calls internationally and block private callers like GrandCentral. Definitely a life saver.

[JohnnyGTO @ Jul 21st 2008 5:28PM]

I haven't answered a blocked call all year, Call-vantage sends them to voice mail which is now full of lots of click, buzzzzzzz. Guess telemarketers ( that's to nice a term ,voice spammer is better) don't leave messages.