Posts Tagged: Gemini Advisory


29
Oct 19

Takeaways from the $566M BriansClub breach

Reporting on the exposure of some 26 million stolen credit cards leaked from a top underground cybercrime store highlighted some persistent and hard truths. Most notably, that the world’s largest financial institutions tend to have a much better idea of which merchants and bank cards have been breached than do the thousands of smaller banks and credit unions across the United States. Also, a great deal of cybercrime seems to be perpetrated by a relatively small number of people.

In September, an anonymous source sent KrebsOnSecurity a link to a nearly 10 gb set of files that included data for approximately 26 million credit and debit cards stolen from hundreds — if not thousands — of hacked online and brick-and-mortar businesses over the past four years.

The data was taken from BriansClub, an underground “carding” store that has (ab)used this author’s name, likeness and reputation in its advertising since 2015. The card accounts were stolen by hackers or “resellers” who make a living breaking into payment card systems online and in the real world. Those resellers then share the revenue from any cards sold through BriansClub.

KrebsOnSecurity shared a copy of the BriansClub card database with Gemini Advisory, a New York-based company that monitors BriansClub and dozens of other carding shops to learn when new cards are added.

Gemini estimates that the 26 million cards — 46 percent credit cards and 54 percent debit cards — represent almost one-third of the existing 87 million credit and debit card accounts currently for sale in the underground.

“While many of these cards were added in previous years, more than 21.6 million will not expire until after October 2019, offering cybercriminal buyers ample opportunity to cash out these records,” Gemini wrote in an analysis of the BriansClub data shared with this author.

Cards stolen from U.S. residents made up the bulk of the data set (~24 million of the 26+ million cards), and as a result these far more plentiful cards were priced much lower than cards from banks outside the U.S. Between 2016 and 2019, cards stolen from U.S.-based bank customers fetched between $12.76 and $16.80 apiece, while non-U.S. cards were priced between $17.04 and $35.70 during the same period.

Image: Gemini Advisory.

Unfortunately for cybercrime investigators, the person who hacked BriansClub has not released (at least not to this author) any information about the BriansClub users, payments, vendors or resellers. [Side note: This hasn’t stopped an unscrupulous huckster from approaching several of my financial industry sources with unlikely offers of said data in exchange for bitcoin].

But the database does have records of which cards were sold and which resellers (identified only by a unique number) supplied those cards, Gemini found.

“While neither the vendor nor the buyer usernames appeared in this database, they were each assigned ID numbers,” Gemini wrote. “This allowed analysts to determine how prolific certain threat actors were on BriansClub and derive relevant metrics from this data.”

According to Gemini, there were 142 resellers and more than 50,000 buyers of the card data sold through BriansClub. These buyers purchased at least 9 million of the 27.2 million cards available. Continue reading →


15
Oct 19

“BriansClub” Hack Rescues 26M Stolen Cards

BriansClub,” one of the largest underground stores for buying stolen credit card data, has itself been hacked. The data stolen from BriansClub encompasses more than 26 million credit and debit card records taken from hacked online and brick-and-mortar retailers over the past four years, including almost eight million records uploaded to the shop in 2019 alone.

An ad for BriansClub has been using my name and likeness for years to peddle millions of stolen credit cards.

Last month, KrebsOnSecurity was contacted by a source who shared a plain text file containing what was claimed to be the full database of cards for sale both currently and historically through BriansClub[.]at, a thriving fraud bazaar named after this author. Imitating my site, likeness and namesake, BriansClub even dubiously claims a copyright with a reference at the bottom of each page: “© 2019 Crabs on Security.”

Multiple people who reviewed the database shared by my source confirmed that the same credit card records also could be found in a more redacted form simply by searching the BriansClub Web site with a valid, properly-funded account.

All of the card data stolen from BriansClub was shared with multiple sources who work closely with financial institutions to identify and monitor or reissue cards that show up for sale in the cybercrime underground.

The leaked data shows that in 2015, BriansClub added just 1.7 million card records for sale. But business would pick up in each of the years that followed: In 2016, BriansClub uploaded 2.89 million stolen cards; 2017 saw some 4.9 million cards added; 2018 brought in 9.2 million more.

Between January and August 2019 (when this database snapshot was apparently taken), BriansClub added roughly 7.6 million cards.

Most of what’s on offer at BriansClub are “dumps,” strings of ones and zeros that — when encoded onto anything with a magnetic stripe the size of a credit card — can be used by thieves to purchase electronics, gift cards and other high-priced items at big box stores.

As shown in the table below (taken from this story), many federal hacking prosecutions involving stolen credit cards will for sentencing purposes value each stolen card record at $500, which is intended to represent the average loss per compromised cardholder.

The black market value, impact to consumers and banks, and liability associated with different types of card fraud.

STOLEN BACK FAIR AND SQUARE

An extensive analysis of the database indicates BriansClub holds approximately $414 million worth of stolen credit cards for sale, based on the pricing tiers listed on the site. That’s according to an analysis by Flashpoint, a security intelligence firm based in New York City.

Allison Nixon, the company’s director of security research, said the data suggests that between 2015 and August 2019, BriansClub sold roughly 9.1 million stolen credit cards, earning the site $126 million in sales (all sales are transacted in bitcoin).

If we take just the 9.1 million cards that were confirmed sold through BriansClub, we’re talking about more than $4 billion in likely losses at the $500 average loss per card figure from the Justice Department.

Also, it seems likely the total number of stolen credit cards for sale on BriansClub and related sites vastly exceeds the number of criminals who will buy such data. Shame on them for not investing more in marketing!

There’s no easy way to tell how many of the 26 million or so cards for sale at BriansClub are still valid, but the closest approximation of that — how many unsold cards have expiration dates in the future — indicates more than 14 million of them could still be valid.

The archive also reveals the proprietor(s) of BriansClub frequently uploaded new batches of stolen cards — some just a few thousand records, and others tens of thousands.

That’s because like many other carding sites, BriansClub mostly resells cards stolen by other cybercriminals — known as resellers or affiliates — who earn a percentage from each sale. It’s not yet clear how that revenue is shared in this case, but perhaps this information will be revealed in further analysis of the purloined database. Continue reading →


30
Apr 19

Data: E-Retail Hacks More Lucrative Than Ever

For many years and until quite recently, credit card data stolen from online merchants has been worth far less in the cybercrime underground than cards pilfered from hacked brick-and-mortar stores. But new data suggests that over the past year, the economics of supply-and-demand have helped to double the average price fetched by card-not-present data, meaning cybercrooks now have far more incentive than ever to target e-commerce stores.

Traditionally, the average price for card data nabbed from online retailers — referred to in the underground as “CVVs” — has ranged somewhere between $2 and $8 per account. CVVs are are almost exclusively purchased by criminals looking to make unauthorized purchases at online stores, a form of thievery known as “card not present” fraud.

In contrast, the value of “dumps” — hacker slang for card data swiped from compromised retail stores, hotels and restaurants with the help of malware installed on point-of-sale systems — has long hovered around $15-$20 per card. Dumps allow street thieves to create physical clones of debit and credit cards, which are then used to perpetrate so-called “card present” fraud at brick and mortar stores.

But according to Gemini Advisory, a New York-based company that works with financial institutions to monitor dozens of underground markets trafficking in both types of data, over the past year the demand for CVVs has far outstripped supply, bringing prices for both CVVs and dumps roughly in line with each other.

Median price of card not present (CNP) vs. card-present (CP) over the past year. Image: Gemini

Stas Alforov, director of research and development at Gemini, says his company is currently monitoring most underground stores that peddle stolen card data — including such heavy hitters as Joker’s Stash, Trump’s Dumps, and BriansDump.

Contrary to popular belief, when these shops sell a CVV or dump, that record is then removed from the inventory of items for sale, allowing companies that track such activity to determine roughly how many new cards are put up for sale and how many have sold. Underground markets that do otherwise quickly earn a reputation among criminals for selling unreliable card data and are soon forced out of business.

“We can see in pretty much real-time what’s being sold and which marketplaces are the most active or have the highest number of records and where the bad guys shop the most,” Alforov said. “The biggest trend we’ve seen recently is there appears to be a much greater demand than there is supply of card not present data being uploaded to these markets.”

Alforov said dumps are still way ahead in terms of the overall number of compromised records for sale. For example, over the past year Gemini has seen some 66 million new dumps show up on underground markets, and roughly half as many CVVs.

“The demand for card not present data remains strong while the supply is not as great as the bad guys need it to be, which means prices have been steadily going up,” Alforov said. “A lot of the bad guys who used to do card present fraud are now shifting to card-not-present fraud.”

One likely reason for that shift is the United States is the last of the G20 nations to make the transition to more secure chip-based payment cards, which is slowly making it more difficult and expensive for thieves to turn dumps into cold hard cash. This same increase in card-not-present fraud has occurred in virtually every other country that long ago made the chip card transition, including AustraliaCanadaFrance and the United Kingdom.

The increasing value of CVV data may help explain why we’ve seen such a huge uptick over the past year in e-commerce sites getting hacked. In a typical online retailer intrusion, the attackers will use vulnerabilities in content management systems, shopping cart software, or third-party hosted scripts to upload malicious code that snarfs customer payment details directly from the site before it can be encrypted and sent to card processors. Continue reading →