Entries Tagged "fraud"

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Interesting Attack on the EMV Smartcard Payment Standard

It’s complicated, but it’s basically a man-in-the-middle attack that involves two smartphones. The first phone reads the actual smartcard, and then forwards the required information to a second phone. That second phone actually conducts the transaction on the POS terminal. That second phone is able to convince the POS terminal to conduct the transaction without requiring the normally required PIN.

From a news article:

The researchers were able to demonstrate that it is possible to exploit the vulnerability in practice, although it is a fairly complex process. They first developed an Android app and installed it on two NFC-enabled mobile phones. This allowed the two devices to read data from the credit card chip and exchange information with payment terminals. Incidentally, the researchers did not have to bypass any special security features in the Android operating system to install the app.

To obtain unauthorized funds from a third-party credit card, the first mobile phone is used to scan the necessary data from the credit card and transfer it to the second phone. The second phone is then used to simultaneously debit the amount at the checkout, as many cardholders do nowadays. As the app declares that the customer is the authorized user of the credit card, the vendor does not realize that the transaction is fraudulent. The crucial factor is that the app outsmarts the card’s security system. Although the amount is over the limit and requires PIN verification, no code is requested.

The paper: “The EMV Standard: Break, Fix, Verify.”

Abstract: EMV is the international protocol standard for smartcard payment and is used in over 9 billion cards worldwide. Despite the standard’s advertised security, various issues have been previously uncovered, deriving from logical flaws that are hard to spot in EMV’s lengthy and complex specification, running over 2,000 pages.

We formalize a comprehensive symbolic model of EMV in Tamarin, a state-of-the-art protocol verifier. Our model is the first that supports a fine-grained analysis of all relevant security guarantees that EMV is intended to offer. We use our model to automatically identify flaws that lead to two critical attacks: one that defrauds the cardholder and another that defrauds the merchant. First, criminals can use a victim’s Visa contact-less card for high-value purchases, without knowledge of the card’s PIN. We built a proof-of-concept Android application and successfully demonstrated this attack on real-world payment terminals. Second, criminals can trick the terminal into accepting an unauthentic offline transaction, which the issuing bank should later decline, after the criminal has walked away with the goods. This attack is possible for implementations following the standard, although we did not test it on actual terminals for ethical reasons. Finally, we propose and verify improvements to the standard that prevent these attacks, as well as any other attacks that violate the considered security properties.The proposed improvements can be easily implemented in the terminals and do not affect the cards in circulation.

Posted on September 14, 2020 at 6:21 AMView Comments

Amazon Supplier Fraud

Interesting story of an Amazon supplier fraud:

According to the indictment, the brothers swapped ASINs for items Amazon ordered to send large quantities of different goods instead. In one instance, Amazon ordered 12 canisters of disinfectant spray costing $94.03. The defendants allegedly shipped 7,000 toothbrushes costing $94.03 each, using the code for the disinfectant spray, and later billed Amazon for over $650,000.

In another instance, Amazon ordered a single bottle of designer perfume for $289.78. In response, according to the indictment, the defendants sent 927 plastic beard trimmers costing $289.79 each, using the ASIN for the perfume. Prosecutors say the brothers frequently shipped and charged Amazon for more than 10,000 units of an item when it had requested fewer than 100. Once Amazon detected the fraud and shut down their accounts, the brothers allegedly tried to open new ones using fake names, different email addresses, and VPNs to obscure their identity.

It all worked because Amazon is so huge that everything is automated.

Posted on August 26, 2020 at 6:31 AMView Comments

Adversarial Machine Learning and the CFAA

I just co-authored a paper on the legal risks of doing machine learning research, given the current state of the Computer Fraud and Abuse Act:

Abstract: Adversarial Machine Learning is booming with ML researchers increasingly targeting commercial ML systems such as those used in Facebook, Tesla, Microsoft, IBM, Google to demonstrate vulnerabilities. In this paper, we ask, “What are the potential legal risks to adversarial ML researchers when they attack ML systems?” Studying or testing the security of any operational system potentially runs afoul the Computer Fraud and Abuse Act (CFAA), the primary United States federal statute that creates liability for hacking. We claim that Adversarial ML research is likely no different. Our analysis show that because there is a split in how CFAA is interpreted, aspects of adversarial ML attacks, such as model inversion, membership inference, model stealing, reprogramming the ML system and poisoning attacks, may be sanctioned in some jurisdictions and not penalized in others. We conclude with an analysis predicting how the US Supreme Court may resolve some present inconsistencies in the CFAA’s application in Van Buren v. United States, an appeal expected to be decided in 2021. We argue that the court is likely to adopt a narrow construction of the CFAA, and that this will actually lead to better adversarial ML security outcomes in the long term.

Medium post on the paper. News article, which uses our graphic without attribution.

Posted on July 23, 2020 at 6:03 AMView Comments

Cryptocurrency Pump and Dump Scams

Really interesting research: “An examination of the cryptocurrency pump and dump ecosystem“:

Abstract: The surge of interest in cryptocurrencies has been accompanied by a proliferation of fraud. This paper examines pump and dump schemes. The recent explosion of nearly 2,000 cryptocurrencies in an unregulated environment has expanded the scope for abuse. We quantify the scope of cryptocurrency pump and dump schemes on Discord and Telegram, two popular group-messaging platforms. We joined all relevant Telegram and Discord groups/channels and identified thousands of different pumps. Our findings provide the first measure of the scope of such pumps and empirically document important properties of this ecosystem.

Posted on June 24, 2020 at 6:30 AMView Comments

Clarifying the Computer Fraud and Abuse Act

A federal court has ruled that violating a website’s terms of service is not “hacking” under the Computer Fraud and Abuse Act.

The plaintiffs wanted to investigate possible racial discrimination in online job markets by creating accounts for fake employers and job seekers. Leading job sites have terms of service prohibiting users from supplying fake information, and the researchers worried that their research could expose them to criminal liability under the CFAA, which makes it a crime to “access a computer without authorization or exceed authorized access.”

So in 2016 they sued the federal government, seeking a declaration that this part of the CFAA violated the First Amendment.

But rather than addressing that constitutional issue, Judge John Bates ruled on Friday that the plaintiffs’ proposed research wouldn’t violate the CFAA’s criminal provisions at all. Someone violates the CFAA when they bypass an access restriction like a password. But someone who logs into a website with a valid password doesn’t become a hacker simply by doing something prohibited by a website’s terms of service, the judge concluded.

“Criminalizing terms-of-service violations risks turning each website into its own criminal jurisdiction and each webmaster into his own legislature,” Bates wrote.

Bates noted that website terms of service are often long, complex, and change frequently. While some websites require a user to read through the terms and explicitly agree to them, others merely include a link to the terms somewhere on the page. As a result, most users aren’t even aware of the contractual terms that supposedly govern the site. Under those circumstances, it’s not reasonable to make violation of such terms a criminal offense, Bates concluded.

This is not the first time a court has issued a ruling in this direction. It’s also not the only way the courts have interpreted the frustratingly vague Computer Fraud and Abuse Act.

EDITED TO ADD (4/13): The actual opinion.

Posted on March 31, 2020 at 7:51 AMView Comments

SIM Hijacking

SIM hijacking — or SIM swapping — is an attack where a fraudster contacts your cell phone provider and convinces them to switch your account to a phone that they control. Since your smartphone often serves as a security measure or backup verification system, this allows the fraudster to take over other accounts of yours. Sometimes this involves people inside the phone companies.

Phone companies have added security measures since this attack became popular and public, but a new study (news article) shows that the measures aren’t helping:

We examined the authentication procedures used by five pre-paid wireless carriers when a customer attempted to change their SIM card. These procedures are an important line of defense against attackers who seek to hijack victims’ phone numbers by posing as the victim and calling the carrier to request that service be transferred to a SIM card the attacker possesses. We found that all five carriers used insecure authentication challenges that could be easily subverted by attackers.We also found that attackers generally only needed to target the most vulnerable authentication challenges, because the rest could be bypassed.

It’s a classic security vs. usability trade-off. The phone companies want to provide easy customer service for their legitimate customers, and that system is what’s being exploited by the SIM hijackers. Companies could make the fraud harder, but it would necessarily also make it harder for legitimate customers to modify their accounts.

Posted on January 21, 2020 at 6:30 AMView Comments

Chrome Extension Stealing Cryptocurrency Keys and Passwords

A malicious Chrome extension surreptitiously steals Ethereum keys and passwords:

According to Denley, the extension is dangerous to users in two ways. First, any funds (ETH coins and ERC0-based tokens) managed directly inside the extension are at risk.

Denley says that the extension sends the private keys of all wallets created or managed through its interface to a third-party website located at erc20wallet[.]tk.

Second, the extension also actively injects malicious JavaScript code when users navigate to five well-known and popular cryptocurrency management platforms. This code steals login credentials and private keys, data that it’s sent to the same erc20wallet[.]tk third-party website.

Another example of how blockchain requires many single points of trust in order to be secure.

Posted on January 3, 2020 at 6:09 AMView Comments

The Story of Tiversa

The New Yorker has published the long and interesting story of the cybersecurity firm Tiversa.

Watching “60 Minutes,” Boback saw a remarkable new business angle. Here was a multibillion-dollar industry with a near-existential problem and no clear solution. He did not know it then, but, as he turned the opportunity over in his mind, he was setting in motion a sequence of events that would earn him millions of dollars, friendships with business élites, prime-time media attention, and respect in Congress. It would also place him at the center of one of the strangest stories in the brief history of cybersecurity; he would be mired in lawsuits, countersuits, and counter-countersuits, which would gather into a vortex of litigation so ominous that one friend compared it to the Bermuda Triangle. He would be accused of fraud, of extortion, and of manipulating the federal government into harming companies that did not do business with him. Congress would investigate him. So would the F.B.I.

Posted on December 3, 2019 at 6:19 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.