Posts Tagged: knowledge-based authentication

May 16

Fraudsters Steal Tax, Salary Data From ADP

Identity thieves stole tax and salary data from payroll giant ADP by registering accounts in the names of employees at more than a dozen customer firms, KrebsOnSecurity has learned. ADP says the incidents occurred because the victim companies all mistakenly published sensitive ADP account information online that made those firms easy targets for tax fraudsters.

adpPatterson, N.J.-based ADP provides payroll, tax and benefits administration for more than 640,000 companies. Last week, U.S. Bancorp (U.S. Bank) — the nation’s fifth-largest commercial bank — warned some of its employees that their W-2 data had been stolen thanks to a weakness in ADP’s customer portal.

ID thieves are interested in W-2 data because it contains much of the information needed to fraudulently request a large tax refund from the U.S. Internal Revenue Service (IRS) in someone else’s name. A reader who works at U.S. Bank shared a letter received from Jennie Carlson, the financial institution’s executive vice president of human resources.

“Since April 19, 2016, we have been actively investigating a security incident with our W-2 provider, ADP,” Carlson wrote. “During the course of that investigation we have learned that an external W-2 portal, maintained by ADP, may have been utilized by unauthorized individuals to access your W-2, which they may have used to file a fraudulent income tax return under your name.”

The letter continued:

“The incident originated because ADP offered an external online portal that has been exploited. For individuals who had never used the external portal, a registration had never been established. Criminals were able to take advantage of that situation to use confidential personal information from other sources to establish a registration in your name at ADP. Once the fraudulent registration was established, they were able to view or download your W-2.”

U.S. Bank spokesman Dana Ripley said the letter was sent to a “small population” of the bank’s more than 64,000 employees. Asked to comment on the letter from U.S. Bank, ADP confirmed that the fraud visited upon U.S. Bank also hit “a very small subset” of the ADP’s total customers this year.

ADP emphasized that the fraudsters needed to have the victim’s personal data — including name, date of birth and Social Security number — to successfully create an account in someone’s name. ADP also stressed that this personal data did not come from its systems, and that thieves appeared to already possess that data when they created the unauthorized accounts at ADP’s portal.

ADP Chief Security Officer Roland Cloutier said customers can choose to create an account at the ADP portal for each employee, or they can defer that process to a later date (but employers do have to chose one or the other, Cloutier said).

According to ADP, new users need to be in possession of two other things (in addition to the victim’s personal data) at a minimum in order to create an account: A custom, company-specific link provided by ADP, and a static code assigned to the customer by ADP.

The problem, Cloutier said, seems to stem from ADP customers that both deferred that signup process for some or all of their employees and at the same time inadvertently published online the link and the company code. As a result, for users who never registered, criminals were able to register as them with fairly basic personal info, and access W-2 data on those individuals. Continue reading →

Feb 16

IRS: 390K More Victims of IRS.Gov Weakness

The U.S. Internal Revenue Service (IRS) today sharply revised previous estimates on the number of citizens that had their tax data stolen since 2014 thanks to a security weakness in the IRS’s own Web site. According to the IRS, at least 724,000 citizens had their personal and tax data stolen after crooks figured out how to abuse a (now defunct) IRS Web site feature called “Get Transcript” to steal victim’s prior tax data.

The Growing Tax Fraud MenaceThe number is more than double the figures the IRS released in August 2015, when it said some 334,000 taxpayers had their data stolen via authentication weaknesses in the agency’s Get Transcript feature.

Turns out, those August 2015 estimates were more than tripled from May 2015, when the IRS shut down its Get Transcript feature and announced it thought crooks had abused the Get Transcript feature to pull previous year’s tax data on just 110,000 citizens.

In a statement released today, the IRS said a more comprehensive, nine-month review of the Get Transcript feature since its inception in January 2014 identified the “potential access of approximately 390,000 additional taxpayer accounts during the period from January 2014 through May 2015.”

The IRS said an additional 295,000 taxpayer transcripts were targeted but access was not successful, and that mailings notifying these taxpayers will start February 29. The agency said it also is offering free credit monitoring through Equifax for affected consumers, and placing extra scrutiny on tax returns from citizens with affected SSNs.

The criminal Get Transcript requests fuel refund fraud, which involves crooks claiming a large refund in the name of someone else and intercepting the payment. Victims usually first learn of the crime after having their returns rejected because scammers beat them to it. Even those who are not required to file a return can be victims of refund fraud, as can those who are not actually due a refund from the IRS.

As I warned in March 2015, the flawed Get Transcript function at issue required taxpayers who wished to obtain a copy of their most recent tax transcript had to provide the IRS’s site with the following information: The applicant’s name, date of birth, Social Security number and filing status. After that data was successfully supplied, the IRS used a service from credit bureau Equifax that asks four so-called “knowledge-based authentication” (KBA) questions. Anyone who succeeds in supplying the correct answers could see the applicant’s full tax transcript, including prior W2s, current W2s and more or less everything one would need to fraudulently file for a tax refund.

These KBA questions — which involve multiple choice, “out of wallet” questions such as previous address, loan amounts and dates — can be successfully enumerated with random guessing. But in practice it is far easier, as we can see from the fact that thieves were successfully able to navigate the multiple questions more than half of the times they tried. The IRS said it identified some 1.3 million attempts to abuse the Get Transcript service since its inception in January 2014; in 724,000 of those cases the thieves succeeded in answering the KBA questions correctly.

The IRS’s answer to tax refund victims — the Identity Protection (IP) PIN — is just as flawed as the now defunct Get Transcript system. These IP PINS, which the IRS has already mailed to some 2.7 million tax ID theft victims, must be supplied on the following year’s tax application before the IRS will accept the return.

The only problem with this approach is that the IRS allows IP PIN recipients to retrieve their PIN via the agency’s Web site, after supplying the answers to the same type of KBA questions from Equifax that opened the Get Transcript feature to exploitation by fraudsters.  These KBA questions focus on things such as previous address, loan amounts and dates and can be successfully enumerated with random guessing.  In many cases, the answers can be found by consulting free online services, such as Zillow and Facebook.

ID thieves understand this all to well, and even a relatively unsophisticated gang engaged in this activity can make millions via tax refund fraud. Last week, a federal grand jury in Oregon unsealed indictments against three men accused of using the IRS’s Get Transcript feature to obtain 1,200 taxpayers transcripts. In total, the authorities allege the men filed over 2,900 false federal tax returns seeking over $25 million in fraudulent refunds.  The IRS says it rejected most of those claims, but that the gang managed to successfully obtain $4.7 million in illegal refunds.

Continue reading →

Mar 15

Intuit Failed at ‘Know Your Customer’ Basics

Intuit, the makers of TurboTax, recently introduced several changes to beef up the security of customer accounts following a spike in tax refund fraud at the state and federal level. Unfortunately, those changes don’t go far enough. Here’s a look at some of the missteps that precipitated this mess, and what the company can do differently going forward.

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As The Wall Street Journal noted in a story this week, competitors H&R Block and TaxAct say they haven’t seen a similar surge in fraud this year. Perhaps the bad guys are just picking on the industry leader. But with 29 million customers last year — far more than H&R Block or TaxAct (which each had about seven million) — TurboTax should also be leading the industry in security.

Keep in mind that none of the security steps described below are going to stop fraud alone. But taken together, they do or would provide more robust security for TurboTax accounts, and significantly raise the costs for criminals engaged in this type of fraud.


Intuit fails to take basic steps to validate key account information, such as email addresses and mobile numbers, and these failures have limited the company’s ability to enact stricter account security measures. In fact, TurboTax still does not require new users to verify their email address, a basic security precaution that even random Internet forums which don’t collect nearly as much sensitive data require of all new users.

Last month, KrebsOnSecurity featured an in-depth story that stemmed from information provided by two former Intuit security employees who accused the company of making millions of dollars knowingly processing tax refund requests filed by cybercriminals. Those individuals shared a great deal about Intuit’s internal discussions on how best to handle a spike in account takeovers and fraudsters using stolen personal information to file tax refund requests on unwitting consumers.

Both whistleblowers said the lack of email verification routinely led to bizarre scenarios in which customers would complain of seeing other peoples’ tax data in their accounts. These were customers who’d forgotten their passwords and entered their email address at the site to receive a password reset link, only to find their email address tied to multiple identities that belonged to other victims of stolen identity refund fraud.

In mid-February, Intuit announced that it would begin the process of prompting all users to validate their accounts, either by validating their email address, answering a set of knowledge-based authentication questions, or entering a code sent to their mobile phone.

In an interview today, Intuit’s leadership sidestepped questions about why the company still does not validate email addresses. But TurboTax Chief Information Security Officer Indu Kodukula did say TurboTax will no longer display multiple profiles tied to a single email address when users attempt to reset their passwords by supplying an email address.

“We had an option where when you entered an email address, we’d show you a list of user IDs that were associated with that address,” Kodukula said. “We’ve removed that option, so now if you try to do password recovery, you have to go back to the email associated with you.” Continue reading →

Sep 14

In Wake of Confirmed Breach at Home Depot, Banks See Spike in PIN Debit Card Fraud

Nearly a week after this blog first reported signs that Home Depot was battling a major security incident, the company has acknowledged that it suffered a credit and debit card breach involving its U.S. and Canadian stores dating back to April 2014. Home Depot was quick to assure customers and banks that no debit card PIN data was compromised in the break-in. Nevertheless, multiple financial institutions contacted by this publication are reporting a steep increase over the past few days in fraudulent ATM withdrawals on customer accounts.


The card data for sale in the underground that was stolen from Home Depot shoppers allows thieves to create counterfeit copies of debit and credit cards that can be used to purchase merchandise in big box stores. But if the crooks who buy stolen debit cards also are able to change the PIN on those accounts, the fabricated debit cards can then be used to withdraw cash from ATMs.

Experts say the thieves who are perpetrating the debit card fraud are capitalizing on a glut of card information stolen from Home Depot customers and being sold in cybercrime shops online. Those same crooks also are taking advantage of weak authentication methods in the automated phone systems that many banks use to allow customers to reset the PINs on their cards.

Here’s the critical part: The card data stolen from Home Depot customers and now for sale on the crime shop Rescator[dot]cc includes both the information needed to fabricate counterfeit cards as well as the legitimate cardholder’s full name and the city, state and ZIP of the Home Depot store from which the card was stolen (presumably by malware installed on some part of the retailer’s network, and probably on each point-of-sale device).

This is especially helpful for fraudsters since most Home Depot transactions are likely to occur in the same or nearby ZIP code as the cardholder. The ZIP code data of the store is important because it allows the bad guys to quickly and more accurately locate the Social Security number and date of birth of cardholders using criminal services in the underground that sell this information.

Why do the thieves need Social Security and date of birth information? Countless banks in the United States let customers change their PINs with a simple telephone call, using an automated call-in system known as a Voice Response Unit (VRU). A large number of these VRU systems allow the caller to change their PIN provided they pass three out of five security checks. One is that the system checks to see if the call is coming from a phone number on file for that customer. It also requests the following four pieces of information:

-the 3-digit code (known as a card verification value or CVV/CV2) printed on the back of the debit card;
-the card’s expiration date;
-the customer’s date of birth;
-the last four digits of the customer’s Social Security number.

On Thursday, I spoke with a fraud fighter at a bank in New England that experienced more than $25,000 in PIN debit fraud at ATMs in Canada. The bank employee said thieves were able to change the PINs on the cards using the bank’s automated VRU system. In this attack, the fraudsters were calling from disposable, prepaid Magic Jack telephone numbers, and they did not have the Cv2 for each card. But they were able to supply the other three data points.

KrebsOnSecurity also heard from an employee at a much larger bank on the West Coast that lost more than $300,000 in two hours today to PIN fraud on multiple debit cards that had all been used recently at Home Depot. The manager said the bad guys called the customer service folks at the bank and provided the last four of each cardholder’s Social Security number, date of birth, and the expiration date on the card. And, as with the bank in New England, that was enough information for the bank to reset the customer’s PIN.

The fraud manager said the scammers in this case also told the customer service people they were traveling in Italy, which made two things possible: It raised the withdrawal limits on the debit cards and allowed thieves to withdraw $300,000 in cash from Italian ATMs in the span of less than 120 minutes. Continue reading →