Entries Tagged "phones"

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Caller ID Spoofing

What’s worse than a bad authentication system? A bad authentication system that people have learned to trust. According to the Associated Press:

In the last few years, Caller ID spoofing has become much easier. Millions of people have Internet telephone equipment that can be set to make any number appear on a Caller ID system. And several Web sites have sprung up to provide Caller ID spoofing services, eliminating the need for any special hardware.

For instance, Spoofcard.com sells a virtual “calling card” for $10 that provides 60 minutes of talk time. The user dials a toll-free number, then keys in the destination number and the Caller ID number to display.

Near as anyone can tell, this is perfectly legal. (Although the FCC is investigating.)

The applications for Caller ID spoofing are not limited to fooling people. There’s real fraud that can be committed:

Lance James, chief scientist at security company Secure Science Corp., said Caller ID spoofing Web sites are used by people who buy stolen credit card numbers. They will call a service such as Western Union, setting Caller ID to appear to originate from the card holder’s home, and use the credit card number to order cash transfers that they then pick up.

Exposing a similar vulnerability, Caller ID is used by credit-card companies to authenticate newly issued cards. The recipients are generally asked to call from their home phones to activate their cards.

And, of course, harmful pranks:

In one case, SWAT teams surrounded a building in New Brunswick, N.J., last year after police received a call from a woman who said she was being held hostage in an apartment. Caller ID was spoofed to appear to come from the apartment.

It’s also easy to break into a cell phone voice mailbox using spoofing, because many systems are set to automatically grant entry to calls from the owner of the account. Stopping that requires setting a PIN code or password for the mailbox.

I have never been a fan of Caller ID. My phone number is configured to block Caller ID on outgoing calls. The number of phone numbers that refuse to accept my calls is growing, however.

Posted on March 3, 2006 at 7:10 AM

More on Greek Wiretapping

Earlier this month I blogged about a wiretapping scandal in Greece.

Unknowns tapped the mobile phones of about 100 Greek politicians and offices, including the U.S. embassy in Athens and the Greek prime minister.

Details are sketchy, but it seems that a piece of malicious code was discovered by Ericsson technicians in Vodafone’s mobile phone software. The code tapped into the conference call system. It “conference called” phone calls to 14 prepaid mobile phones where the calls were recorded.

More details are emerging. It turns out that the “malicious code” was actually code designed into the system. It’s eavesdropping code put into the system for the police.

The attackers managed to bypass the authorization mechanisms of the eavesdropping system, and activate the “lawful interception” module in the mobile network. They then redirected about 100 numbers to 14 shadow numbers they controlled. (Here are translations of some of the press conferences with technical details. And here are details of the system used.)

There is an important security lesson here. I have long argued that when you build surveillance mechanisms into communication systems, you invite the bad guys to use those mechanisms for their own purposes. That’s exactly what happened here.

UPDATED TO ADD (3/2): From a reader: “I have an update. There is some news from the ‘Hellenic Authority for the Information and Communication Security and Privacy’ with a few facts and I got a rumor that there is a root backdoor in the telnetd of Ericssons AXE backdoor. (No, I can’t confirm the rumor.)”

Posted on March 1, 2006 at 8:04 AMView Comments

Phone Tapping in Greece

Unknowns tapped the mobile phones of about 100 Greek politicians and offices, including the U.S. embassy in Athens and the Greek prime minister.

Details are sketchy, but it seems that a piece of malicious code was discovered by Ericsson technicians in Vodafone’s mobile phone software. The code tapped into the conference call system. It “conference called” phone calls to 14 prepaid mobile phones where the calls were recorded.

Some details are here. See also this news article, and — if you can read Greek — this one.

Posted on February 3, 2006 at 11:27 AMView Comments

Anyone Can Get Anyone's Phone Records

Interested in who your spouse is talking to? Your boss? A celebrity? A politician?

The Chicago Police Department is warning officers their cell phone records are available to anyone — for a price. Dozens of online services are selling lists of cell phone calls, raising security concerns among law enforcement and privacy experts….

How well do the services work? The Chicago Sun-Times paid $110 to Locatecell.com to purchase a one-month record of calls for this reporter’s company cell phone. It was as simple as e-mailing the telephone number to the service along with a credit card number. The request was made Friday after the service was closed for the New Year’s holiday.

On Tuesday, when it reopened, Locatecell.com e-mailed a list of 78 telephone numbers this reporter called on his cell phone between Nov. 19 and Dec. 17. The list included calls to law enforcement sources, story subjects and other Sun-Times reporters and editors.

EDITED TO ADD (1/9): More information on BoingBoing.

EDITED TO ADD (1/9): Also see this on EPIC West.

EDITED TO ADD (1/14): Daniel Solove has some good commentary.

Posted on January 9, 2006 at 6:59 AMView Comments

Electronic Shackles and Telephone Communications

The article is in Hebrew, but the security story is funny in any language.

It’s about a prisoner who was forced to wear an electronic shackle to monitor that he did not violate his home arrest. The shackle is pretty simple: if the suspect leaves the defined detention area, the electronic shackle signals through the telephone line to the local police.

How do you defeat a system such as this? Just stop paying your phone bill and wait for the phone company to shut off service.

Posted on December 21, 2005 at 12:03 PMView Comments

Cell Phone Companies and Security

This is a fascinating story of cell phone fraud, security, economics, and externalities. Its moral is obvious, and demonstrates how economic considerations drive security decisions.

Susan Drummond was a customer of Rogers Wireless, a large Canadaian cell phone company. Her phone was cloned while she was on vacation, and she got a $12,237.60 phone bill (her typical bill was $75). Rogers maintains that there is nothing to be done, and that Drummond has to pay.

Like all cell phone companies, Rogers has automatic fraud detection systems that detect this kind of abnormal cell phone usage. They don’t turn the cell phones off, though, because they don’t want to annoy their customers.

Ms. Hopper [a manager in Roger’s security department] said terrorist groups had identified senior cellphone company officers as perfect targets, since the company was loath to shut off their phones for reasons that included inconvenience to busy executives and, of course, the public-relations debacle that would take place if word got out.

As long as Rogers can get others to pay for the fraud, this makes perfect sense. Shutting off a phone based on an automatic fraud-detection system costs the phone company in two ways: people inconvenienced by false alarms, and bad press. But the major cost of not shutting off a phone remains an externality: the customer pays for it.

In fact, there seems be some evidence that Rogers decides whether or not to shut off a suspecious phone based on the customer’s ability to pay:

Ms. Innes [a vice-president with Rogers Communications] said that Rogers has a policy of contacting consumers if fraud is suspected. In some cases, she admitted, phones are shut off automatically, but refused to say what criteria were used. (Ms. Drummond and Mr. Gefen believe that the company bases the decision on a customer’s creditworthiness. “If you have the financial history, they let the meter run,” Ms. Drummond said.) Ms. Drummond noted that she has a salary of more than $100,000, and a sterling credit history. “They knew something was wrong, but they thought they could get the money out of me. It’s ridiculous.”

Makes sense from Rogers’ point of view. High-paying customers are 1) more likely to pay, and 2) more damaging if pissed off in a false alarm. Again, economic considerations trump security.

Rogers is defending itself in court, and shows no signs of backing down:

In court filings, the company has made it clear that it intends to hold Ms. Drummond responsible for the calls made on her phone. “. . . the plaintiff is responsible for all calls made on her phone prior to the date of notification that her phone was stolen,” the company says. “The Plaintiff’s failure to mitigate deprived the Defendant of the opportunity to take any action to stop fraudulent calls prior to the 28th of August 2005.”

The solution here is obvious: Rogers should not be able to charge its customers for telephone calls they did not make. Ms. Drummond’s phone was cloned; there is no possible way she could notify Rogers of this before she saw calls she did not make on her bill. She is also completely powerless to affect the anti-cloning security in the Rogers phone system. To make her liable for the fraud is to ensure that the problem never gets fixed.

Rogers is the only party in a position to do something about the problem. The company can, and according to the article has, implemented automatic fraud-detection software.

Rogers customers will pay for the fraud in any case. If they are responsible for the loss, either they’ll take their chances and pay a lot only if they are the victims, or there’ll be some insurance scheme that spreads the cost over the entire customer base. If Rogers is responsible for the loss, then the customers will pay in the form of slightly higher prices. But only if Rogers is responsible for the loss will they implement security countermeasures to limit fraud.

And if they do that, everyone benefits.

There is a Slashdot thread on the topic.

Posted on December 19, 2005 at 1:10 PMView Comments

U.S. Compromises Canadian Privacy

A Canadian reporter was able to get phone records for the personal and professional accounts held by Canadian Privacy Commissioner Jennifer Stoddart through an American data broker, locatecell.com. The security concerns are obvious.

Canada has an exception in the privacy laws that allows newspapers to do this type of investigative reporting. My guess is that’s the only reason we haven’t seen an American reporter pull phone records on one of our government officials.

Posted on November 17, 2005 at 2:32 PMView Comments

Stride-Based Security

Can a cell phone detect if it is stolen by measuring the gait of the person carrying it?

Researchers at the VTT Technical Research Centre of Finland have developed a prototype of a cell phone that uses motion sensors to record a user’s walking pattern of movement, or gait. The device then periodically checks to see that it is still in the possession of its legitimate owner, by measuring the current stride and comparing it against that stored in its memory.

Clever, as long as you realize that there are going to be a lot of false alarms. This seems okay:

If the phone suspects it has fallen into the wrong hands, it will prompt the user for a password if they attempt to make calls or access its memory.

Posted on November 16, 2005 at 6:26 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.