LAS VEGAS — A security researcher created a cell phone base station that tricks cell phones into routing their outbound calls through his device, allowing someone to intercept even encrypted calls in the clear.
The device tricks the phones into disabling encryption and records call details and content before they’re routed on their proper way through voice-over-IP.
The low-cost, home-brewed device, developed by researcher Chris Paget, mimics more expensive devices already used by intelligence and law enforcement agencies – called IMSI catchers – that can capture phone ID data and content. The devices essentially spoof a legitimate GSM tower and entice cell phones to send them data by emitting a signal that’s stronger than legitimate towers in the area.
“If you have the ability to deliver a reasonably strong signal, then those around are owned,” Paget said.
Paget’s system costs only about $1,500, as opposed to several hundreds of thousands for professional products. Most of the price is for the laptop he used to operate the system.
Doing this kind of interception “used to be a million dollars, now you can do it with a thousand times less cost,” Paget said during a press conference after his attack. “If it’s $1,500, it’s just beyond the range that people can start buying them for themselves and listening in on their neighbors.”
Paget’s device captures only 2G GSM calls, making AT&T and T-Mobile calls, which use GSM, vulnerable to interception. Paget’s aim was to highlight vulnerabilities in the GSM standard that allows a rogue station to capture calls. GSM is a second-generation technology that is not as secure as 3G technology.
Encrypted calls are not protected from interception because the rogue tower can simply turn it off. Although the GSM specifications say that a phone should pop up a warning when it connects to a station that does not have encryption, SIM cards disable that setting so that alerts are not displayed.
“Even though the GSM spec requires it, this is a deliberate choice on the cell phone makers,” Paget said.
The system captures only outbound calls. Inbound calls would go directly to voicemail during the period that someone’s phone is connected to Paget’s tower.
The device could be used by corporate spies, criminals, or private investigators to intercept private calls of targets.
“Any information that goes across a cell phone you can now intercept,” he said, except data. Professional grade IMSI catchers do capture data transfers, but Paget’s system doesn’t currently do this.
His setup included two RF directional antennas about three feet long to amplify his signal in the large conference room, a laptop and open source software. The system emitted only 25 milliwatts, “a hundred times less than your average cell phone,” he said.
Paget received a call from FCC officials on Friday who raised a list of possible regulations his demonstration might violate. To get around legal concerns, he broadcast on a GSM spectrum for HAM radios, 900Mhz, which is the same frequency used by GSM phones and towers in Europe, thus avoiding possible violations of U.S. regulations.
Just turning on the antennas caused two dozen phones in the room to connect to Paget’s tower. He then set it to spoof an AT&T tower to capture calls from customers of that carrier.
“As far as your cell phones are concerned, I am now indistinguishable from AT&T,” he said. “Every AT&T cell phone in the room will gradually start handing over to my network.”
During the demonstration, only about 30 phones were actually connecting to his tower. Paget says it can take time for phones to find the signal and hand off to the tower, but there are methods for speeding up that process.
To address privacy concerns, he set up the system to deliver a recorded message to anyone who tried to make a call from the room while connected to his tower. The message disclosed that their calls were being recorded. All of the data Paget recorded was saved to a USB stick, which he destroyed after the talk.
Customers of carriers that use GSM could try to protect their calls from being intercepted in this manner by switching their phones to 3G mode if it’s an option.
But Paget said he could also capture phones using 3G by sending out jamming noise to block 3G. Phones would then switch to 2G and hook up with his rogue tower. Paget had his jammer and an amplifier on stage but declined to turn them on saying they would “probably knock out all Las Vegas cell phone systems.”
Photo: Dave Bullock
Black Hat Independent researchers have made good on a promise to release a comprehensive set of tools needed to eavesdrop on cell phone calls that use the world’s most widely deployed mobile technology.
“The whole topic of GSM hacking now enters the script-kiddie stage, similar to Wi-Fi hacking a couple years ago, where people started cracking the neighbor’s Wi-Fi,” said Karsten Nohl, a cryptographer with the Security Research Labs in Berlin who helped spearhead the project. “Just as with Wi-Fi, where they changed the encryption to WPA, hopefully that will happen with GSM, too.”
The suite of applications now includes Kraken, software being released at the Black Hat security conference on Thursday that can deduce the secret key encrypting SMS messages and voice conversations in as little as 30 seconds. It was developed by Frank A. Stevenson, the same Norwegian programmer who almost a decade ago developed software that cracked the CSS encryption schemeprotecting DVDs.
GSM insecurity is largely the result of widely known weaknesses in A5/1, the algorithm used to decrypt calls in most of the developed world. Years ago, mobile operators devised A5/3, which requires some quintillion more mathematical operations to be cracked. It has yet to be adopted as mobile operators fret that the change will be expensive and won’t work on older handsets. Many countries continue to use A5/0, which uses no meaningful encryption at all.
“It’s really interesting to watch a phone number turn into a person’s life,” security researcher Nick DePetrillo told the Los Angeles Times in a report published yesterday. According to Petrillo and fellow expert Don Bailey, the mere digits of your cell phone number can betray your name, your travel itinerary, and your work and home address; it can also allow others to listen in on your voice messages and personal phone calls.
Using “widely available information and existing techniques,” DePetrillo and Bailey reportedly were able to construct detailed files on a cellphone user. Find out how after the break.
As “white hat hackers,” meaning the good guys that hack you to expose security gaps and then figure ways to patch them, DePetrillo and Bailey have learned that by using special software to spoof a call from the target number, tricking the cell phone company into thinking the call is coming from the target’s cell phone: The Caller ID system then identifies the victim’s name for you. As the LA Times points out, a hacker could create their own phonebook of numbers and corresponding identities.
From there, the hacker can then query the cellphone network to discover the location of the phone. Websites such as InstaMapper are openly accessible and free to use. With this, one can hypothetically track and generate a general schedule of your movements.
Moreover, there is always the possibility of malicious applications, which appear to do one thing but in reality can collect private information. For example, security expert Tyler Shields created an application called “TXSBBSPY,” which when installed on a Blackberry, could read text messages, listen to voice mail, and even turn on the phone’s mic at will.
Today, smartphones including the iPhone, Blackberry, and Android devices comprise about 21% of the cell phone market, and often contain sensitive information like other phone numbers, e-mails, and banking information. Nielsen Co. estimates the smartphone to become the new standard by 2011. However, as the smartphone is a recent development, Shields says that we are only living in the “late ’90s” when it comes to mobile security.
The obvious solutions, of course, are to 1) keep your cell phone number private; 2) shield your number with services like Google Voice; 3) use common sense – don’t access suspicious software and links.
With traditional identity theft channels now closing, fraudsters are increasingly targeting unprotected voice conversations to obtain confidential insider information, passwords and PIN codes without detection. Voice correspondence is almost always uncharted territory for business security armour under the false assumption that phone hacking is a highly sophisticated and expensive means of attack.
The days of phone fraud involving thousands of pounds of equipment and an extensive army of technology experts are long gone. Only in December it was revealed that a computer engineer had broken the algorithm used to encrypt the majority of the world’s digital mobile phone calls online, and published his method…
Web posted at: 4/14/2010 1:36:44
Source ::: REUTERS
BOGOTA: Colombian President Alvaro Uribe said yesterday that a widening wiretap scandal, in which five former intelligence officers were arrested, is being orchestrated to damage his image before May’s election.
Uribe, a conservative barred by the constitution from seeking a third term, remains popular despite a series of scandals involving state security forces accused of violating rights. His former Defense Minister Juan Manuel Santos leads the opinion polls ahead of the May 30 presidential vote.
One of five former agents arrested over the weekend for wiretapping judges, reporters and opposition politicians said that the program of illegally listening in on telephone conversations was directed from the presidential palace.
Uribe denies the charge, which is being investigated by the attorney general’s office. “What a coincidence that this is happening during an election campaign,” Uribe told a local radio station.
Supreme Court Justice Cesar Valencia, whose telephone was tapped, says the bugging was ordered from high levels. “It was a criminal enterprise directed by the presidential palace,” he told El Tiempo newspaper.