All About Skimmers


1
Feb 13

Pro-Grade Point-of-Sale Skimmer

Every so often, the sophistication of the technology being built into credit card skimmers amazes even the experts who are accustomed to studying such crimeware. This post focuses on one such example — images from one of several compromised point-of-sale devices that used Bluetooth technology to send the stolen data to the fraudsters wirelessly.

This point-of-sale device was one of several found in an as-yet undisclosed merchant breach.

This point-of-sale device was one of several found in an as-yet undisclosed merchant breach.

In October 2012, forensics experts with Trustwave Spiderlabs were called in to examine the handiwork of several Bluetooth based point-of-sale skimmers found at a major U.S. retailer. The skimmers described and pictured in this blog post were retrieved from a retail breach that has not yet been disclosed, said Jonathan Spruill, a security consultant at Trustwave.

Spruill said the card-skimming devices that had been added to the small point-of-sale machines was beyond anything he’d encountered in skimmer technology to date.

“The stuff we’ve been seeing lately is a leap forward in these types of crimes,” said Spruill, a former special agent with the U.S. Secret Service. “You hate to say you admire the work, but at some point you say, ‘Wow, that’s pretty clever.’ From a technical and hardware standpoint, this was really well thought-out.”

Spruill declined to name the breached merchant, and said it was unclear how long the devices had been in place prior to their discovery, or how they were introduced into the stores. But the incident is the latest in a string of breaches involving bricks-and-mortar merchants discovering compromised point-of-sale devices at their retail stores. Late last year, bookseller Barnes & Noble disclosed that it had found modified point-of-sale devices at 60 locations nationwide.

The picture below shows the card skimmer in more detail. The entire green square circuit board with the grey square heat shield and the blue element to the left are the brains of the device. The eight-legged black component in the upper right is the memory module that stored stolen credit and debit card and PIN data from unwitting store customers.

Beneath the large grey heat shield in the center of the circuit board are the chips that control the Bluetooth radio. That entire component is soldered to the base of the board. The blue and white wires leading from the skimming device connect the skimming module to the card reader on the point-of-sale device, while the group of eight orange wires that come out of the bottom connect directly to the device’s PIN pad.

The Bluetooth point-of-sale skimmer, up close.

The Bluetooth point-of-sale skimmer, up close.

The image below shows the eight orange wires from the skimmer soldered to the POS device. Spruill said the quality of the soldering job indicates this was not made by some kid in his mom’s basement.

“One of the reasons suggesting that the attacker was fairly accomplished is the quality of the solder done with those very small connections to the PIN pad,” he said.

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18
Dec 12

Point-of-Sale Skimmers: No Charge…Yet

If you hand your credit or debit card to a merchant who is using a wireless point-of-sale (POS) device, you may want to later verify that the charge actually went through. A top vendor of POS skimmers ships devices that will print out “transaction approved” receipts, even though the machine is offline and is merely recording the customer’s card data and PIN for future fraudulent use.

This skimmer seller is a major vendor on one of the Underweb’s most active fraud forums. Being a “verified” vendor on this fraud forum — which comes with the stamp of approval from the forum administrators, thus, enhancing the seller’s reputation — costs $5,000 annually. But this seller can make back his investment with just two sales, and judging from the volume of communications he receives from forum members, business is brisk.

This miscreant sells two classes of pre-hacked wireless Verifone POS devices: The Verifone vx670, which he sells for $2,900 plus shipping, and a Verifone vx510, which can be had for $2,500. Below is a video he posted to youtube.com showing a hacked version of the vx510 printing out a fake transaction approval receipt.

From the seller’s pitch: “POS is ‘fake’ and stores D+P [card data and PIN], prints out approved receipt or can be setup for connection error. Software to decrypt the data is provided. It keeps d+p inside memory for manual retrieval via USB cable.”

These types of hacked POS systems, known as “offline POS skimmers” in the Underweb, are marketed for suggested use by miscreants employed in seasonal or temporary work, such as in restaurants, bars or retail establishments.

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4
Dec 12

ATM Thieves Swap Security Camera for Keyboard

This blog has featured stories about a vast array of impressive, high-tech devices used to steal money from automated teller machines (ATMs). But every so often thieves think up an innovation that makes all of the current ATM skimmers look like child’s play. Case in point: Authorities in Brazil have arrested a man who allegedly stole more than USD $41,000 from an ATM after swapping its security camera with a portable keyboard that let him hack the cash machine.

Photo: TV Bahia

The story comes from O Estado de S. Paulo (“The State of São Paulo“), a daily newspaper in Brazil’s largest city. According to the paper, late last month a crook approached an ATM at the Bank of Brazil and somehow removed the security camera from the machine. Apparently, the camera was a USB-based device, because the thief then was able to insert his own USB stick into the slot previously occupied by the camera. As you can imagine, a scene straight out of Terminator 2 ensued.

The attacker was then able to connect a folding keyboard to the ATM’s computer and restart the machine. The newspaper story isn’t crystal clear on the role of the USB device — whether it served as a replacement operating system or merely served to connect the keyboard to the machine (it’s not hard to imagine why this would be so easy, since most ATMs run on some version of Microsoft Windows, which automatically installs drivers for most USB-based input devices).

At any rate, after the thief rebooted the ATM’s computer, he was reportedly able to type the value of the currency notes that he intended to withdraw. According to the story, the thief started by removing all of the R $100 bills, and then moved on to the R $50 notes, and so on.

A crude skimming device removed from an Inova Hospital in Fairfax, Va. last month.

A crude skimming device removed from an Inova Hospital in Fairfax, Va. last month.

As clever as this hack was, the crook didn’t get away: The police were alerted by the central bank’s security team, and caught the thief in the process of withdrawing the funds. Brazilian authorities said they believe the man was being coached via phone, but that the guy they apprehended refused to give up the identity of his accomplice. My guess is the one coaching the thief had inside knowledge about how these machines operated, and perhaps even worked at a financial institution at one point.

These kinds of attacks make traditional ATM skimmer scams look positively prehistoric by comparison. But the sad part is that even really crude skimming devices can be very lucrative and go undetected for months. I was reminded of this last week, when, for the third time in as many months, authorities discovered ATM skimmers at hospitals within a few miles of here. Local police believe the same thieves are responsible for planting all of the fraud devices, which are relatively unsophisticated but nonetheless enabled the theft of thousands of dollars over a period of several weeks.

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20
Nov 12

Beware Card- and Cash-Trapping at the ATM

Many security-savvy readers of this blog have learned to be vigilant against ATM card skimmers and hidden devices that can record you entering your PIN at the cash machine. But experts say an increasing form of ATM fraud involves the use of simple devices capable of snatching cash and ATM cards from unsuspected users.

Security experts with the European ATM Security Team (EAST) say five countries in the region this year have reported card trapping incidents. Such attacks involve devices that fit over the card acceptance slot and include a razor-edged spring trap that prevents the customer’s card from being ejected from the ATM when the transaction is completed.

These devices were made to capture the ATM user’s card after the user withdrawals cash. Credit: EAST.

“Spring traps are still being widely used,” EAST wrote in its most recently European Fraud Update. “Once the card has been inserted, these prevent the card being returned to the customer and also stop the ATM from retracting it. According to reports from one country – despite warning messages that appear on the ATM screen or are displayed on the ATM fascia – customers are still not reporting when their cards are captured, leading to substantial losses from ATM or point-of-sale
transactions.”

According to EAST, most card trapping incidents take place outside normal banking hours with initial fraudulent usage taking place within 10 minutes of the card capture (balance inquiry and cash withdrawal at a nearby ATM), followed by point-of-sale transactions.

A twist on this attack involves “cash traps,” often claw-like contraptions that thieves insert into the cash-dispensing slot which are capable of capturing or skimming some of the dispensed bills. Here are a few pictures of a cash-trapping device from an EAST report released earlier this year.

Claw-like cash trap devices found inserted into ATMs in Europe. Source: EAST.

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12
Sep 12

Researchers: Chip and PIN Enables ‘Chip and Skim’

Researchers in the United Kingdom say they’ve discovered mounting evidence that thieves have been quietly exploiting design flaws in a security system widely used in Europe to prevent credit and debit card fraud at cash machines and point-of-sale devices.

The innards of a chip-and-PIN enabled card.

At issue is an anti-fraud system called EMV (short for Europay, MasterCard and Visa), more commonly known as “chip-and-PIN.” Most European banks have EMV-enabled cards, which include a secret algorithm embedded in a chip that encodes the card data, making it more difficult for fraudsters to clone the cards for use at EMV-compliant terminals. Chip-and-PIN is not yet widely supported in the United States, but the major card brands are pushing banks and ATM makers to support the technology within the next two to three years.

EMV standards call for cards to be authenticated to a payment terminal or ATM by computing several bits of information, including the charge or withdrawal amount, the date, and a so-called “unpredictable number”. But researchers from the computer laboratory at Cambridge University say they discovered that some payment terminals and ATMs rely on little more than simple counters, or incrementing numbers that are quite predictable.

“The current problem is that instead of having the random number generated by the bank, it’s generated by the merchant terminal,” said Ross Anderson, professor of security engineering at Cambridge, and an author of a paper being released this week titled, “Chip and Skim: Cloning EMV cards with the Pre-Play Attack.”

Anderson said that the failure to specify that merchant terminals should insist on truly *random* numbers, instead of merely non-repeating numbers — is at the crux of the problem.

“This leads to two potential failures: If the merchant terminal doesn’t a generate random number, you’re stuffed,” he said in an interview. “And the second is if there is some wicked interception device between the merchant terminal and the bank, such as malware on the merchant’s server, then you’re also stuffed.”

The “pre-play” aspect of the attack mentioned in the title of their paper refers to the ability to predict the unpredictable number, which theoretically allows an attacker to record everything from the card transaction and to play it back and impersonate the card in additional transactions at a future date and location.

Anderson and a team of other researchers at Cambridge launched their research more than nine months ago, when they first began hearing from European bank card users who said they’d been victimized by fraud — even though they had not shared their PIN with anyone. The victims’ banks refused to reimburse the losses, arguing that the EMV technology made the claimed fraud impossible. But the researchers suspected that fraudsters had discovered a method of predicting the supposedly unpredictable number implementation used by specific point-of-sale devices or ATMs models.

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5
Sep 12

A Handy Way to Foil ATM Skimmer Scams

I spent several hours this past week watching video footage from hidden cameras that skimmer thieves placed at ATMs to surreptitiously record customers entering their PINs. I was surprised to see that out of the dozens of customers that used the compromised cash machines, only one bothered to take the simple but effective security precaution of covering his hand when entering his 4-digit code.

In February 2011, I wrote about geek gear used in a 2009 ATM skimmer incident at a Bank of America branch in California. The theft devices employed in that foiled attack included a card skimmer that fit over the real card acceptance slot, and a hidden ball camera.

I recently obtained the video footage recorded by that hidden ball camera. The first segment shows the crook installing the skimmer cam at a drive-up ATM early on a Sunday morning. The first customer arrives just seconds after the fraudster drives away, entering his PIN without shielding the keypad and allowing the camera to record his code. Dozens of customers after him would do the same. One of the customers in the video clip below voices a suspicion that something isn’t quite right about the ATM, but he proceeds to enter his PIN and withdraw cash anyhow. A few seconds later, the hidden camera records him reciting the PIN for his ATM card, and asking his passenger to verify the code.

Some readers may thinking, “Wait a minute: Isn’t it more difficult to use both hands when you’re withdrawing cash from a drive-thru ATM while seated in your car?” Maybe. You might think, then, that it would be more common to see regular walk-up ATM users observing this simple security practice. But that’s not what I found after watching 90 minutes of footage from another ATM scam that was recently shared by a law enforcement source. In this attack, the fraudster installed an all-in-one skimmer, and none of the 19 customers caught on camera before the scheme was foiled made any effort to shield the PIN pad.

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24
Jul 12

ATM Skimmers Get Wafer Thin

It’s getting harder to detect some of the newer ATM skimmers, fraud devices attached to or inserted into cash machines and designed to steal card and PIN data. Among the latest and most difficult-to-spot skimmer innovations is a wafer-thin card reading device that can be inserted directly into the ATM’s card acceptance slot.

That’s according to two recent reports from the European ATM Security Team (EAST), an organization that collects ATM fraud reports from countries in the region. In both reports, EAST said one country (it isn’t naming which) alerted them about a new form of skimming device that is thin enough to be inserted directly into the card reader slot. These devices record the data stored on the magnetic stripe on the back of the card as it is slid into a compromised ATM.

Wafer-thin skimmers like these are showing up in ATMs in one European nation. Images courtesy EAST.

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25
Apr 12

Skimtacular: All-in-One ATM Skimmer

I spent the past week vacationing (mostly) in Southern California, traveling from Los Angeles to Santa Barbara and on to the wine country in Santa Ynez. Along the way, I received some information from a law enforcement source in the area about a recent ATM skimmer attack that showcased a well-designed and stealthy all-in-one skimmer.

The skimmer pictured below is the backside of a card acceptance slot overlay. It was recovered by a customer at a bank in the San Fernando Valley who called the cops upon her discovery. Police in the region still have no leads on who might have placed the device. The numeral “5” engraved in the upper right portion of this skimmer suggests that it was one in a series of fraud devices produced by this skimmer maker.

Backside of an all-in-one ATM skimmer found this year at a bank in the San Fernando Valley area of California.

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7
Dec 11

Pro Grade (3D Printer-Made?) ATM Skimmer

In July 2011, a customer at a Chase Bank branch in West Hills, Calif. noticed something odd about the ATM he was using and reported it to police. Authorities who responded to the incident discovered a sophisticated, professional-grade ATM skimmer that they believe was made with the help of a 3D printer.

Below is a front view image of the device. It is an all-in-one skimmer designed to fit over the card acceptance slot and to record the data from the magnetic stripe of any card dipped into the reader. The fraud device is shown sideways in this picture; attached to an actual ATM, it would appear rotated 90 degrees to the right, so that the word “CHASE” is pointing down.

On the bottom of the fake card acceptance slot is a tiny hole for a built-in spy camera that is connected to a battery. The spy camera turns on when a card is dipped into the skimmer’s card acceptance slot, and is angled to record customer PINs.

The bottom of the skimmer device is designed to overlay the controls on the cash machine for vision impaired ATM users. On the underside of that space is a data port to allow manual downloading of information from the skimmer.

Looking at the backside of the device shows shows the true geek factor of this ATM skimmer. The fraudster who built it appears to have cannibalized parts from a video camera or perhaps a smartphone (possibly to enable the transmission of  PIN entry video and stolen card data to the fraudster wirelessly via SMS or Bluetooth). It’s too bad so much of the skimmer is obscured by yellow plastic. I’d welcome any feedback from readers who can easily identify these parts based on the limited information here. Continue reading →


13
Oct 11

ATM Skimmer Powered by MP3 Player

Almost a year ago, I wrote about ATM skimmers made of parts from old MP3 players. Since then, I’ve noticed quite a few more ads for these MP3-powered skimmers in the criminal underground, perhaps because audio skimmers allow fraudsters to sell lucrative service contracts along with their theft devices.

Using audio to capture credit and debit card data is not a new technique, but it is becoming vogue: Square, an increasingly popular credit card reader built for the iPhone, works by plugging into the headphone jack on the iPhone and converting credit card data stored on the card into audio files.

An audio skimmer for a Diebold ATM.

The device pictured here is a card skimmer designed to fit over the card acceptance slot on a Diebold Opteva 760, one of the most common ATMs around. The green circuit board on the left was taken from an MP3 player (no idea which make or model). When a card is slid past the magnetic reader (the small black rectangle at the end of the black and red wires near the center of the picture), the MP3 player “hears” the data stored on the card’s magnetic stripe, and records it as an audio file to a tiny embedded flash memory device.

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