Posts Tagged: citibank


28
Apr 20

Would You Have Fallen for This Phone Scam?

You may have heard that today’s phone fraudsters like to use caller ID spoofing services to make their scam calls seem more believable. But you probably didn’t know that these fraudsters also can use caller ID spoofing to trick your bank into giving up information about recent transactions on your account — data that can then be abused to make their phone scams more believable and expose you to additional forms of identity theft.

Last week, KrebsOnSecurity told the harrowing tale of a reader (a security expert, no less) who tried to turn the tables on his telephonic tormentors and failed spectacularly. In that episode, the people impersonating his bank not only spoofed the bank’s real phone number, but they were also pretending to be him on a separate call at the same time with his bank.

This foiled his efforts to make sure it was really his bank that called him, because he called his bank with another phone and the bank confirmed they currently were in a separate call with him discussing fraud on his account (however, the other call was the fraudster pretending to be him).

Shortly after that story ran, I heard from another reader — we’ll call him “Jim” since he didn’t want his real name used for this story — whose wife was the target of a similar scam, albeit with an important twist: The scammers were armed with information about a number of her recent financial transactions, which he claims they got from the bank’s own automated phone system just by spoofing her phone number.

“When they originally called my wife, there were no fraudulent transactions on her account, but they were able to specify the last three transactions she had made, which combined with the caller-ID had mistakenly earned her trust,” Jim explained. “After we figured out what was going on, we were left asking ourselves how the crooks had obtained her last three transactions without breaking into her account online. As it turned out, calling the phone number on the back of the credit card from the phone number linked with the card provided the most recent transactions without providing any form of authentication.”

Jim said he was so aghast at this realization that he called the same number from his phone and tried accessing his account, which is also at Citi but wholly separate from his spouse’s. Sure enough, he said, as long as he was calling from the number on file for his account, the automated system let him review recent transactions without any further authentication.

“I confirmed on my separate Citi card that they often (but not quite always) were providing the transaction details,” Jim said. “I was appalled that Citi would do that. So, it seemed the crooks would spoof caller ID when calling Citibank, as well as when calling the target/victim.

The incident Jim described happened in late January 2020, and Citi may have changed its procedures since then. But in a phone interview with KrebsOnSecurity earlier this week, Jim made a call to Citi’s automated system from his mobile phone on file with the bank, and I could hear Citi’s systems asking him to enter the last four digits of his credit card number before he could review recent transactions.

The request for the last four of the customer’s credit card number was consistent with my own testing, which relied on a caller ID spoofing service advertised in the cybercrime underground and aimed at a Citi account controlled by this author.

In one test, the spoofed call let KrebsOnSecurity hear recent transaction data — where and when the transaction was made, and how much was spent — after providing the automated system the last four digits of the account’s credit card number. In another test, the automated system asked for the account holder’s full Social Security number.

Citi declined to discuss specific actions it takes to detect and prevent fraud. But in a written statement provided to this author it said the company continuously monitors and analyzes threats and looks for opportunities to strengthen its controls.

“We see regular attempts by fraudsters to gain access to information and we are constantly monitoring for emerging threats and taking preventive action for our clients’ protection,” the statement reads. “For inbound calls to call centers, we continue to adapt and implement detection capabilities to identify suspicious or spoofed phone numbers. We also encourage clients to install and use our mobile app and sign up for push notifications and alerts in the mobile app.”

PREGNANT PAUSES AND BULGING EMAIL BOMBS

Jim said the fraudster who called his wife clearly already knew her mailing and email addresses, her mobile number and the fact that her card was an American Airlines-branded Citi card. The caller said there had been a series of suspicious transactions, and proceeded to read back details of several recent transactions to verify if those were purchases she’d authorized.

A list of services offered by one of several underground stores that sell caller ID spoofing and email bombing services.

Jim’s wife quickly logged on to her Citi account and saw that the amounts, dates and places of the transactions referenced by the caller indeed corresponded to recent legitimate transactions. But she didn’t see any signs of unauthorized charges.

After verifying the recent legitimate transactions with the caller, the person on the phone asked for her security word. When she provided it, there was a long hold before the caller came back and said she’d provided the wrong answer.

When she corrected herself and provided a different security word, there was another long pause before the caller said the second answer she provided was correct. At that point, the caller said Citi would be sending her a new card and that it had prevented several phony charges from even posting to her account.

She didn’t understand until later that the pauses were points at which the fraudsters had to put her on hold to relay her answers in their own call posing as her to Citi’s customer service department.

Not long after Jim’s spouse hung up with the caller, her inbox quickly began filling up with hundreds of automated messages from various websites trying to confirm an email newsletter subscription she’d supposedly requested.

As the recipient of several of theseemail bombing” attacks, I can verify that crooks often will use services offered in the cybercrime underground to flood a target’s inbox with these junk newsletter subscriptions shortly after committing fraud in the target’s name when they wish to bury an email notification from a target’s bank.

‘OVERPAYMENT REIMBURSEMENT’

In the case of Jim’s wife, the inbox flood backfired, and only made her more suspicious about the true nature of the recent phone call. So she called the number on the back of her Citi card and was told that she had indeed just called Citi and requested what’s known as an “overpayment reimbursement.” The couple have long had their credit cards on auto-payment, and the most recent payment was especially high — nearly $4,000 — thanks to a flurry of Christmas present purchases for friends and family.

In an overpayment reimbursement, a customer can request that the bank refund any amount paid toward a previous bill that exceeds the minimum required monthly payment. Doing so causes any back-due interest on that unpaid amount to accrue to the account as well.

In this case, the caller posing as Jim’s wife requested an overpayment reimbursement to the tune of just under $4,000. It’s not clear how or where the fraudsters intended this payment to be sent, but for whatever reason Citi ended up saying they would cut a physical check and mail it to the address on file. Probably not what the fraudsters wanted, although since then Jim and his wife say they have been on alert for anyone suspicious lurking near their mailbox.

“The person we spoke with at Citi’s fraud department kept insisting that yes, it was my wife that called because the call came from her mobile number,” Jim said. “The Citi employee was alarmed because she didn’t understand the whole notion of caller ID spoofing. And we both found it kind of disturbing that someone in fraud at such a major bank didn’t even understand that such a thing was possible.” Continue reading →


6
Mar 13

Mobile Malcoders Pay to (Google) Play

An explosion in malware targeting Android users is being fueled in part by a budding market for mobile malcode creation kits, as well as a brisk market for hijacked or fraudulent developer accounts at Google Play that can be used to disguise malware as legitimate apps for sale.

An Underweb ad for Perkele

An Underweb ad for Perkele

I recently encountered an Android malware developer on a semi-private Underweb forum who was actively buying up verified developer accounts at Google Play for $100 apiece. Google charges just $25 for Android developers who wish to sell their applications through the Google Play marketplace, but it also requires the accounts to be approved and tied to a specific domain. The buyer in this case is offering $100 for sellers willing to part with an active, verified Play account that  is tied to a dedicated server.

Unsurprisingly, this particular entrepreneur also sells an Android SMS malware package that targets customers of Citibank, HSBC and ING, as well as 66 other financial institutions in Australia, France, India, Italy, Germany, New Zealand, Singapore, Spain, Switzerland and Turkey (the complete list is here). The targeted banks offer text messages as a form of multi-factor authentication, and this bot is designed to intercept all incoming SMS messages on infected Android phones.

This bot kit — dubbed “Perkele” by a malcoder who goes by the same nickname (‘perkele’ is a Finnish curse word for “devil” or “damn”) — does not appear to be terribly diabolical or sophisticated as modern mobile malware goes. Still, judging from the number and reputation of forum buyers who endorsed Perkele’s malware, it appears quite popular and to perform as advertised.

Continue reading →


28
Jan 13

Big Bank Mules Target Small Bank Businesses

A $170,000 cyberheist last month against an Illinois nursing home provider starkly illustrates how large financial institutions are being leveraged to target security weaknesses at small to regional banks and credit unions.

I have written about more than 80 organizations that were victims of cyberheists, and a few recurring themes have emerged from nearly all of these breaches. First, a majority of the victim organizations banked at smaller institutions. Second, virtually all of the money mules — willing or unwitting individuals recruited to help launder the stolen funds — used accounts at the top five largest U.S. banks.

The attack on Niles Nursing Inc. provides a textbook example. On Monday, Dec. 17, 2012, computer crooks logged into the company’s online banking accounts using the controller’s credentials and tunneling their connection through his hacked PC. At the beginning of the heist, the miscreants added 11 money mules to Niles’ payroll, sending them automated clearing house (ACH) payments totaling more than $58,000, asking each mule to withdraw their transfers in cash and wire the money to individuals in Ukraine and Russia.

nilesmulespartNiles’ financial institution — Ft. Lauderdale, Fla. based Optimum Bank — evidently saw nothing suspicious about 11 new employees scattered across five states being added to its customer’s payroll overnight. From the bank’s perspective, the user submitting the payroll batch logged in to the account with the proper credentials and with the same PC that was typically used to administer the account. The thieves would put through another two fraudulent payment batches over next two days (the bank blocked the last batch on the 19th).

In total, the attackers appear to have recruited at least two dozen money mules to help haul the stolen loot. All but two of the mules used or opened accounts at four out of five of the nation’s top U.S. banks, including Bank of America, Chase, Citibank, and Wells Fargo. No doubt these institutions together account for a huge percentage of the retail banking accounts in America today, but interviews with mules recruited by this crime gang indicate that they were instructed to open accounts at these institutions if they did not already have them.

ANALYSIS

I’ve spoken at numerous financial industry conferences over the past three years to talk about these cyberheists, and one question I am almost always asked is, “Is it safer for businesses to bank at larger institutions?” This is a tricky question to answer because banking online remains a legally and financially risky affair for any business, regardless of which bank it uses. Businesses do not enjoy the same fraud protections as consumers; if a Trojan lets the bad guys siphon an organization’s online accounts, that victim organization is legally responsible for the loss. The financial institution may decide to reimburse the victim for some or all of the costs of the fraud, but that is entirely up to the bank.

What’s more, it is likely that fewer cyberheists involving customers of Top 5 banks ever see the light of day, principally because the larger banks are in a better financial position to assume responsibility for some or all of the loss (provided, of course, that the victim in return agrees not to sue the bank or disclose the breach publicly).

I prefer to answer the question as if I were a modern cyberthief in charge of selecting targets. The organized crooks behind these attacks blast out tens of millions of booby-trapped emails daily, and undoubtedly have thousands of stolen online banking credentials to use at any one time. There are more than 7,000 financial institutions in the United States…should I choose a target at one of the top 10 banks? These institutions hold a majority of the financial industry’s assets, and they’re accustomed to moving huge sums of money around each day.

On the other hand, their potential for fraud is almost certainly orders of magnitude greater than at smaller institutions. That would suggest that it may be easier for these larger institutions to justify antifraud expenditures. That incentive to enact antifraud protections is even greater because these institutions have huge numbers of retail customers, a channel in which they legally eat the loss from unauthorized account activity.

Continue reading →


4
Apr 11

Epsilon Breach Raises Specter of Spear Phishing

Security experts are warning consumers to be especially alert for targeted email scams in the coming weeks and months, following a breach at a major email marketing firm that exposed names and email addresses for customers of some of the nation’s largest banks and corporate brand names.

Late last week, Irving, Texas based Epsilon issued a brief statement warning that hackers had stolen customer email addresses and names belonging to a “subset of its clients.” Epsilon didn’t name the clients that had customer data lost in the breach; that information would come trickling out over the weekend, as dozens of major corporations began warning customers to be wary of unsolicited email scams that may impersonate their brands as a result.

Among Epsilon’s clients affected are three of the top ten U.S. banks – JP Morgan Chase, Citibank and U.S. Bank — as well as Barclays Bank and Capital One. More than two dozen other brands have alerted customers to data lost in the Epsilon breach (a list of companies known to have been impacted is at the bottom of this post).

Rod Rasmussen, chief technology officer at Internet Identity and the industry liaison for the Anti-Phishing Working Group, believes that the Epsilon breach will lead to an increase in “spear phishing” attacks, those that take advantage of known trust relationships between corporations and customers by crafting personalized messages that address recipients by name, thereby increasing the apparent authenticity of the email.

“I think this is going to make a big difference in spear phishing, where you may not be targeting an individual, but you know that that person has a bank account with US Bank and recently stayed at Disney,” Rasmussen said. “You now can automate spam based on things people have actually done, so your missive that they need to log into your phishing site is much more affective. You can also correlate across your data to see all the services someone is using, phish them for a user/password on something innocuous, and then re-use the same password for the bank they use, since there’s such rampant password re-use out there.”

Crooks used very similar spear phishing methods to steal customer contact information from dozens of email marketing firms late last year, as KrebsOnSecurity.com first reported in detail. In the wake of that assault, data spills at other email marketing firms like SilverPop have prompted disclosures from clients such as TripAdvisor and Play.com.

Neil Schwartzman, executive director of the Coalition Against Unsolicited Commercial Email (CAUCE) and a former executive at email service provider ReturnPath, said his organization plans to release a document later today spelling out security measures that providers should be taking, such as encrypting customer data.

“There are best practices that the major of the industry should have implemented a year ago, but never did, and it’s just disgusting and reprehensible that they haven’t done this stuff yet,” Schwartzman said. “I’ve talked to people in other industrial sectors who said if my external auditors found out we were treating customer data this way, we’d be in serious trouble.”

Continue reading →


15
Jan 10

Would You Have Spotted the Fraud?

Pictured below is what’s known as a skimmer, or a device made to be affixed to the mouth of an ATM and secretly swipe credit and debit card information when bank customers slip their cards into the machines to pull out money. Skimmers have been around for years, of course, but thieves are constantly improving them, and the device pictured below is a perfect example of that evolution.

This particular skimmer was found Dec. 6, 2009, attached to the front of a Citibank ATM in Woodland Hills, Calif. Would you have been able to spot this?

Continue reading →