Posts Tagged: chip cards


30
Jul 20

Is Your Chip Card Secure? Much Depends on Where You Bank

Chip-based credit and debit cards are designed to make it infeasible for skimming devices or malware to clone your card when you pay for something by dipping the chip instead of swiping the stripe. But a recent series of malware attacks on U.S.-based merchants suggest thieves are exploiting weaknesses in how certain financial institutions have implemented the technology to sidestep key chip card security features and effectively create usable, counterfeit cards.

A chip-based credit card. Image: Wikipedia.

Traditional payment cards encode cardholder account data in plain text on a magnetic stripe, which can be read and recorded by skimming devices or malicious software surreptitiously installed in payment terminals. That data can then be encoded onto anything else with a magnetic stripe and used to place fraudulent transactions.

Newer, chip-based cards employ a technology known as EMV that encrypts the account data stored in the chip. The technology causes a unique encryption key — referred to as a token or “cryptogram” — to be generated each time the chip card interacts with a chip-capable payment terminal.

Virtually all chip-based cards still have much of the same data that’s stored in the chip encoded on a magnetic stripe on the back of the card. This is largely for reasons of backward compatibility since many merchants — particularly those in the United States — still have not fully implemented chip card readers. This dual functionality also allows cardholders to swipe the stripe if for some reason the card’s chip or a merchant’s EMV-enabled terminal has malfunctioned.

But there are important differences between the cardholder data stored on EMV chips versus magnetic stripes. One of those is a component in the chip known as an integrated circuit card verification value or “iCVV” for short — also known as a “dynamic CVV.”

The iCVV differs from the card verification value (CVV) stored on the physical magnetic stripe, and protects against the copying of magnetic-stripe data from the chip and the use of that data to create counterfeit magnetic stripe cards. Both the iCVV and CVV values are unrelated to the three-digit security code that is visibly printed on the back of a card, which is used mainly for e-commerce transactions or for card verification over the phone.

The appeal of the EMV approach is that even if a skimmer or malware manages to intercept the transaction information when a chip card is dipped, the data is only valid for that one transaction and should not allow thieves to conduct fraudulent payments with it going forward.

However, for EMV’s security protections to work, the back-end systems deployed by card-issuing financial institutions are supposed to check that when a chip card is dipped into a chip reader, only the iCVV is presented; and conversely, that only the CVV is presented when the card is swiped. If somehow these do not align for a given transaction type, the financial institution is supposed to decline the transaction.

The trouble is that not all financial institutions have properly set up their systems this way. Unsurprisingly, thieves have known about this weakness for years. In 2017, I wrote about the increasing prevalence of “shimmers,” high-tech card skimming devices made to intercept data from chip card transactions.

A close-up of a shimmer found on a Canadian ATM. Source: RCMP.

More recently, researchers at Cyber R&D Labs published a paper detailing how they tested 11 chip card implementations from 10 different banks in Europe and the U.S. The researchers found they could harvest data from four of them and create cloned magnetic stripe cards that were successfully used to place transactions.

There are now strong indications the same method detailed by Cyber R&D Labs is being used by point-of-sale (POS) malware to capture EMV transaction data that can then be resold and used to fabricate magnetic stripe copies of chip-based cards.

Earlier this month, the world’s largest payment card network Visa released a security alert regarding a recent merchant compromise in which known POS malware families were apparently modified to target EMV chip-enabled POS terminals.

“The implementation of secure acceptance technology, such as EMV® Chip, significantly reduced the usability of the payment account data by threat actors as the available data only included personal account number (PAN), integrated circuit card verification value (iCVV) and expiration date,” Visa wrote. “Thus, provided iCVV is validated properly, the risk of counterfeit fraud was minimal. Additionally, many of the merchant locations employed point-to-point encryption (P2PE) which encrypted the PAN data and further reduced the risk to the payment accounts processed as EMV® Chip.”

Visa did not name the merchant in question, but something similar seems to have happened at Key Food Stores Co-Operative Inc., a supermarket chain in the northeastern United States. Key Food initially disclosed a card breach in March 2020, but two weeks ago updated its advisory to clarify that EMV transaction data also was intercepted.

“The POS devices at the store locations involved were EMV enabled,” Key Food explained. “For EMV transactions at these locations, we believe only the card number and expiration date would have been found by the malware (but not the cardholder name or internal verification code).”

While Key Food’s statement may be technically accurate, it glosses over the reality that the stolen EMV data could still be used by fraudsters to create magnetic stripe versions of EMV cards presented at the compromised store registers in cases where the card-issuing bank hadn’t implemented EMV correctly. Continue reading →


5
Apr 18

Secret Service Warns of Chip Card Scheme

The U.S. Secret Service is warning financial institutions about a new scam involving the temporary theft of chip-based debit cards issued to large corporations. In this scheme, the fraudsters intercept new debit cards in the mail and replace the chips on the cards with chips from old cards. When the unsuspecting business receives and activates the modified card, thieves can start draining funds from the account.

Signs of a card with an old or invalid chip include heat damage around the chip or on the card, or a small hole in the plastic used to pry the chip off the card. Image: U.S. Secret Service.

According to an alert sent to banks late last month, the entire scheme goes as follows:

1. Criminals intercept mail sent from a financial institution to large corporations that contain payment cards, targeting debit payment cards with access to large amount of funds.

2. The crooks remove the chip from the debit payment card using a heat source that warms the glue.

3. Criminals replace the chip with an old or invalid chip and repackage the payment card for delivery.

4. Criminals place the stolen chip into an old payment card.

5. The corporation receives the debit payment card without realizing the chip has been replaced.

6. The corporate office activates the debit payment card; however, their payment card is inoperable thanks to the old chip.

7. Criminals use the payment card with the stolen chip for their personal gain once the corporate office activates the card. Continue reading →


15
Jan 16

Hyatt Card Breach Hit 250 Hotels in 50 Nations

If you stayed, ate or played at a Hyatt hotel between Aug. 13 and Dec. 8, 2015, there’s a good chance your credit or debit card data was stolen by unknown cyber thieves who infiltrated many of the hotel chain’s payment systems. In its first disclosure about the scope of a breach acknowledged last month, Hyatt Hotels Corp. says the intrusion likely affected guests at 250 hotels in roughly 50 countries.

hyattIn a statement released Thursday, Hyatt said the majority of the payment systems compromised by card-stealing malware were at restaurants within the hotels, and that a “small percentage of the at-risk cards were used at spas, golf shops, parking and a limited number of front desks.” The list of affected hotels is here.

Chicago-based Hyatt joins a crowded list of other hotel chains similarly breached in the past year, including Hilton, Starwood, Mandarin Oriental, White Lodging (twice) and the Trump Collection.

ANALYSIS/RANT

U.S. banks have been transitioning to offering chip-based credit and debit cards, and a greater number of retailers are installing checkout systems that can read customer card data off the chip. The chip encrypts the card data and makes it much more difficult and expensive for thieves to counterfeit cards.

However, most of these chip cards will still hold customer data in plain text on the card’s magnetic stripe, and U.S. merchants that continue to allow customers to swipe the stripe or who do not have chip card readers in place face shouldering all of the liability for any transactions later determined to be fraudulent.

The United States is the last of the G20 nations to enact this liability shift, and many countries that have transitioned to chip card technology have done so through government fiat. Those nations also almost uniformly have seen card counterfeiting fraud go way down while thieves shift their attention to targeting e-commerce providers.

Although cyber thieves still steal card data off the magnetic stripe from customers of banks in nations that long ago shifted to chip-cards, that card data is typically shipped to thieves here in the United States, who can counterfeit the cards and use them to steal merchandise from U.S.-based big box retailers.

What’s remarkable about the U.S. experiment with moving to chip cards is that the discussion about whether and when to move to more physical security (chips) in credit and debit cards has played out almost entirely apart from the move to impose expensive and increasingly labyrinthine compliance regulations (PCI) on merchants that wish to process or accept card transactions.
Continue reading →


1
Apr 15

‘Revolution’ Crimeware & EMV Replay Attacks

In October 2014, KrebsOnSecurity examined a novel “replay” attack that sought to exploit implementation weaknesses at U.S. financial institutions that were in the process of transitioning to more secure chip-based credit and debit cards. Today’s post looks at one service offered in the cybercrime underground to help thieves perpetrate this type of fraud.

Several U.S. financial institutions last year reported receiving tens of thousands of dollars in fraudulent credit and debit card transactions coming from Brazil and hitting card accounts stolen in recent retail heists, principally cards compromised as part of the October 2014 breach at Home Depot. The affected banks were puzzled by the attacks because the fraudulent transactions were all submitted through Visa and MasterCard‘s networks as chip-enabled transactions, even though the banks that issued the cards in question hadn’t yet begun sending customers chip-enabled cards.

Seller in underground forum describes his "Revolution" software to conduct  EMV card fraud against banks that haven't implemented EMV correctly .

Seller in underground forum describes his “Revolution” software to conduct EMV card fraud against banks that haven’t implemented EMV fully.

Fraud experts said the most likely explanation for the activity was that crooks were pushing regular magnetic stripe transactions through the card network as chip card purchases using a technique known as a “replay” attack. According to one bank interviewed at the time, MasterCard officials explained that the thieves were likely in control of a payment terminal and had the ability to manipulate data fields for transactions put through that terminal. After capturing traffic from a real chip-based chip card transaction, the thieves could insert stolen card data into the transaction stream, while modifying the merchant and acquirer bank account data on-the-fly.

Recently, KrebsOnSecurity encountered a fraudster in a popular cybercrime forum selling a fairly sophisticated software-as-a-service package to do just that. The seller, a hacker who reportedly specializes in selling skimming products to help thieves steal card data from ATMs and point-of-sale devices, calls his product “Revolution” and offers to provide buyers with a list of U.S. financial institutions that have not fully or properly implemented systems for accepting and validating chip-card transactions. Continue reading →


27
Oct 14

‘Replay’ Attacks Spoof Chip Card Charges

An odd new pattern of credit card fraud emanating from Brazil and targeting U.S. financial institutions could spell costly trouble for banks that are just beginning to issue customers more secure chip-based credit and debit cards.

emvblueOver the past week, at least three U.S. financial institutions reported receiving tens of thousands of dollars in fraudulent credit and debit card transactions coming from Brazil and hitting card accounts stolen in recent retail heists, principally cards compromised as part of the breach at Home Depot.

The most puzzling aspect of these unauthorized charges? They were all submitted through Visa and MasterCard‘s networks as chip-enabled transactions, even though the banks that issued the cards in question haven’t even yet begun sending customers chip-enabled cards.

The most frustrating aspect of these unauthorized charges? They’re far harder for the bank to dispute. Banks usually end up eating the cost of fraud from unauthorized transactions when scammers counterfeit and use stolen credit cards. Even so, a bank may be able to recover some of that loss through dispute mechanisms set up by Visa and MasterCard, as long as the bank can show that the fraud was the result of a breach at a specific merchant (in this case Home Depot).

However, banks are responsible for all of the fraud costs that occur from any fraudulent use of their customers’ chip-enabled credit/debit cards — even fraudulent charges disguised as these pseudo-chip transactions.

CLONED CHIP CARDS, OR CLONED TRANSACTIONS?

The bank I first heard from about this fraud — a small financial institution in New England — battled some $120,000 in fraudulent charges from Brazilian stores in less than two days beginning last week. The bank managed to block $80,000 of those fraudulent charges, but the bank’s processor, which approves incoming transactions when the bank’s core systems are offline, let through the other $40,000. All of the transactions were debit charges, and all came across MasterCard’s network looking to MasterCard like chip transactions without a PIN.

The fraud expert with the New England bank said the institution had decided against reissuing customer cards that were potentially compromised in the five-month breach at Home Depot, mainly because that would mean reissuing a sizable chunk of the bank’s overall card base and because the bank had until that point seen virtually no fraud on the accounts.

“We saw very low penetration rates on our Home Depot cards, so we didn’t do a mass reissue,” the expert said. “And then in one day we matched a month’s worth of fraud on those cards thanks to these charges from Brazil.” Continue reading →