Entries Tagged "crime"

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Tracking Down a Suspect through Cell Phone Records

Interesting forensics in connection with a serial killer arrest:

Investigators went through phone records collected from both midtown Manhattan and the Massapequa Park area of Long Island—two areas connected to a “burner phone” they had tied to the killings. (In court, prosecutors later said the burner phone was identified via an email account used to “solicit and arrange for sexual activity.” The victims had all been Craigslist escorts, according to officials.)

They then narrowed records collected by cell towers to thousands, then to hundreds, and finally down to a handful of people who could match a suspect in the killings.

From there, authorities focused on people who lived in the area of the cell tower and also matched a physical description given by a witness who had seen the suspected killer.

In that narrowed pool, they searched for a connection to a green pickup truck that a witness had seen the suspect driving, the sources said.

Investigators eventually landed on Heuermann, who they say matched a witness’ physical description, lived close to the Long Island cell site and worked near the New York City cell sites that captured the other calls.

They also learned he had often driven a green pickup truck, registered to his brother, officials said. But they needed more than just circumstantial evidence.

Investigators were able to obtain DNA from an immediate family member and send it to a specialized lab, sources said. According to the lab report, Heuermann’s family member was shown to be related to a person who left DNA on a burlap sack containing one of the buried victims.

There’s nothing groundbreaking here; it’s casting a wide net with cell phone geolocation data and then winnowing it down using other evidence and investigative techniques. And right now, those are expensive and time consuming, so only used in major crimes like murder (or, in this case, murders).

What’s interesting to think about is what happens when this kind of thing becomes cheap and easy: when it can all be done through easily accessible databases, or even when an AI can do the sorting and make the inferences automatically. Cheaper digital forensics means more digital forensics, and we’ll start seeing this kind of thing for even routine crimes. That’s going to change things.

Posted on July 17, 2023 at 7:13 AMView Comments

Self-Driving Cars Are Surveillance Cameras on Wheels

Police are already using self-driving car footage as video evidence:

While security cameras are commonplace in American cities, self-driving cars represent a new level of access for law enforcement ­ and a new method for encroachment on privacy, advocates say. Crisscrossing the city on their routes, self-driving cars capture a wider swath of footage. And it’s easier for law enforcement to turn to one company with a large repository of videos and a dedicated response team than to reach out to all the businesses in a neighborhood with security systems.

“We’ve known for a long time that they are essentially surveillance cameras on wheels,” said Chris Gilliard, a fellow at the Social Science Research Council. “We’re supposed to be able to go about our business in our day-to-day lives without being surveilled unless we are suspected of a crime, and each little bit of this technology strips away that ability.”

[…]

While self-driving services like Waymo and Cruise have yet to achieve the same level of market penetration as Ring, the wide range of video they capture while completing their routes presents other opportunities. In addition to the San Francisco homicide, Bloomberg’s review of court documents shows police have sought footage from Waymo and Cruise to help solve hit-and-runs, burglaries, aggravated assaults, a fatal collision and an attempted kidnapping.

In all cases reviewed by Bloomberg, court records show that police collected footage from Cruise and Waymo shortly after obtaining a warrant. In several cases, Bloomberg could not determine whether the recordings had been used in the resulting prosecutions; in a few of the cases, law enforcement and attorneys said the footage had not played a part, or was only a formality. However, video evidence has become a lynchpin of criminal cases, meaning it’s likely only a matter of time.

Posted on July 3, 2023 at 7:04 AMView Comments

Typing Incriminating Evidence in the Memo Field

Don’t do it:

Recently, the manager of the Harvard Med School morgue was accused of stealing and selling human body parts. Cedric Lodge and his wife Denise were among a half-dozen people arrested for some pretty grotesque crimes. This part is also at least a little bit funny though:

Over a three-year period, Taylor appeared to pay Denise Lodge more than $37,000 for human remains. One payment, for $1,000 included the memo “head number 7.” Another, for $200, read “braiiiiiins.”

It’s so easy to think that you won’t get caught.

Posted on June 27, 2023 at 4:36 PMView Comments

Ransomware Payments Are Down

Chainalysis reports that worldwide ransomware payments were down in 2022.

Ransomware attackers extorted at least $456.8 million from victims in 2022, down from $765.6 million the year before.

As always, we have to caveat these findings by noting that the true totals are much higher, as there are cryptocurrency addresses controlled by ransomware attackers that have yet to be identified on the blockchain and incorporated into our data. When we published last year’s version of this report, for example, we had only identified $602 million in ransomware payments in 2021. Still, the trend is clear: Ransomware payments are significantly down.

However, that doesn’t mean attacks are down, or at least not as much as the drastic drop-off in payments would suggest. Instead, we believe that much of the decline is due to victim organizations increasingly refusing to pay ransomware attackers.

Posted on January 31, 2023 at 7:03 AMView Comments

Textbook Rental Scam

Here’s a story of someone who, with three compatriots, rented textbooks from Amazon and then sold them instead of returning them. They used gift cards and prepaid credit cards to buy the books, so there was no available balance when Amazon tried to charge them the buyout price for non-returned books. They also used various aliases and other tricks to bypass Amazon’s fifteen-book limit. In all, they stole 14,000 textbooks worth over $1.5 million.

The article doesn’t link to the indictment, so I don’t know how they were discovered.

EDITED TO ADD (11/12): Press release.

Posted on October 20, 2021 at 6:16 AMView Comments

T-Mobile Data Breach

It’s a big one:

As first reported by Motherboard on Sunday, someone on the dark web claims to have obtained the data of 100 million from T-Mobile’s servers and is selling a portion of it on an underground forum for 6 bitcoin, about $280,000. The trove includes not only names, phone numbers, and physical addresses but also more sensitive data like social security numbers, driver’s license information, and IMEI numbers, unique identifiers tied to each mobile device. Motherboard confirmed that samples of the data “contained accurate information on T-Mobile customers.”

Posted on August 19, 2021 at 6:17 AMView Comments

Disrupting Ransomware by Disrupting Bitcoin

Ransomware isn’t new; the idea dates back to 1986 with the “Brain” computer virus. Now, it’s become the criminal business model of the internet for two reasons. The first is the realization that no one values data more than its original owner, and it makes more sense to ransom it back to them—sometimes with the added extortion of threatening to make it public—than it does to sell it to anyone else. The second is a safe way of collecting ransoms: bitcoin.

This is where the suggestion to ban cryptocurrencies as a way to “solve” ransomware comes from. Lee Reiners, executive director of the Global Financial Markets Center at Duke Law, proposed this in a recent Wall Street Journal op-ed. Journalist Jacob Silverman made the same proposal in a New Republic essay. Without this payment channel, they write, the major ransomware epidemic is likely to vanish, since the only payment alternatives are suitcases full of cash or the banking system, both of which have severe limitations for criminal enterprises.

It’s the same problem kidnappers have had for centuries. The riskiest part of the operation is collecting the ransom. That’s when the criminal exposes themselves, by telling the payer where to leave the money. Or gives out their banking details. This is how law enforcement tracks kidnappers down and arrests them. The rise of an anonymous, global, distributed money-transfer system outside of any national control is what makes computer ransomware possible.

This problem is made worse by the nature of the criminals. They operate out of countries that don’t have the resources to prosecute cybercriminals, like Nigeria; or protect cybercriminals that only attack outside their borders, like Russia; or use the proceeds as a revenue stream, like North Korea. So even when a particular group is identified, it is often impossible to prosecute. Which leaves the only tools left a combination of successfully blocking attacks (another hard problem) and eliminating the payment channels that the criminals need to turn their attacks into profit.

In this light, banning cryptocurrencies like bitcoin is an obvious solution. But while the solution is conceptually simple, it’s also impossible because—despite its overwhelming problems—there are so many legitimate interests using cryptocurrencies, albeit largely for speculation and not for legal payments.

We suggest an easier alternative: merely disrupt the cryptocurrency markets. Making them harder to use will have the effect of making them less useful as a ransomware payment vehicle, and not just because victims will have more difficulty figuring out how to pay. The reason requires understanding how criminals collect their profits.

Paying a ransom starts with a victim turning a large sum of money into bitcoin and then transferring it to a criminal controlled “account.” Bitcoin is, in itself, useless to the criminal. You can’t actually buy much with bitcoin. It’s more like casino chips, only usable in a single establishment for a single purpose. (Yes, there are companies that “accept” bitcoin, but that is mostly a PR stunt.) A criminal needs to convert the bitcoin into some national currency that he can actually save, spend, invest, or whatever.

This is where it gets interesting. Conceptually, bitcoin combines numbered Swiss bank accounts with public transactions and balances. Anyone can create as many anonymous accounts as they want, but every transaction is posted publicly for the entire world to see. This creates some important challenges for these criminals.

First, the criminal needs to take efforts to conceal the bitcoin. In the old days, criminals used “mixing services“: third parties that would accept bitcoin into one account and then return it (minus a fee) from an unconnected set of accounts. Modern bitcoin tracing tools make this money laundering trick ineffective. Instead, the modern criminal does something called “chain swaps.”

In a chain swap, the criminal transfers the bitcoin to a shady offshore cryptocurrency exchange. These exchanges are notoriously weak about enforcing money laundering laws and—for the most part—don’t have access to the banking system. Once on this alternate exchange, the criminal sells his bitcoin and buys some other cryptocurrency like Ethereum, Dogecoin, Tether, Monero, or one of dozens of others. They then transfer it to another shady offshore exchange and transfer it back into bitcoin. Voila­—they now have “clean” bitcoin.

Second, the criminal needs to convert that bitcoin into spendable money. They take their newly cleaned bitcoin and transfer it to yet another exchange, one connected to the banking system. Or perhaps they hire someone else to do this step. These exchanges conduct greater oversight of their customers, but the criminal can use a network of bogus accounts, recruit a bunch of users to act as mules, or simply bribe an employee at the exchange to evade whatever laws there. The end result of this activity is to turn the bitcoin into dollars, euros, or some other easily usable currency.

Both of these steps—the chain swapping and currency conversion—require a large amount of normal activity to keep from standing out. That is, they will be easy for law enforcement to identify unless they are hiding among lots of regular, noncriminal transactions. If speculators stopped buying and selling cryptocurrencies and the market shrunk drastically, these criminal activities would no longer be easy to conceal: there’s simply too much money involved.

This is why disruption will work. It doesn’t require an outright ban to stop these criminals from using bitcoin—just enough sand in the gears in the cryptocurrency space to reduce its size and scope.

How do we do this?

The first mechanism observes that the criminal’s flows have a unique pattern. The overall cryptocurrency space is “zero sum”: Every dollar made was provided by someone else. And the primary legal use of cryptocurrencies involves speculation: people effectively betting on a currency’s future value. So the background speculators are mostly balanced: One bitcoin in results in one bitcoin out. There are exceptions involving offshore exchanges and speculation among different cryptocurrencies, but they’re marginal, and only involve turning one bitcoin into a little more (if a speculator is lucky) or a little less (if unlucky).

Criminals and their victims act differently. Victims are net buyers, turning millions of dollars into bitcoin and never going the other way. Criminals are net sellers, only turning bitcoin into currency. The only other net sellers are the cryptocurrency miners, and they are easy to identify.

Any banked exchange that cares about enforcing money laundering laws must consider all significant net sellers of cryptocurrencies as potential criminals and report them to both in-country and US financial authorities. Any exchange that doesn’t should have its banking forcefully cut.

The US Treasury can ensure these exchanges are cut out of the banking system. By designating a rogue but banked exchange, the Treasury says that it is illegal not only to do business with the exchange but for US banks to do business with the exchange’s bank. As a consequence, the rogue exchange would quickly find its banking options eliminated.

A second mechanism involves the IRS. In 2019, it started demanding information from cryptocurrency exchanges and added a check box to the 1040 form that requires disclosure from those who both buy and sell cryptocurrencies. And while this is intended to target tax evasion, it has the side consequence of disrupting those offshore exchanges criminals rely to launder their bitcoin. Speculation on cryptocurrency is far less attractive since the speculators have to pay taxes but most exchanges don’t help out by filing 1099-Bs that make it easy to calculate the taxes owed.

A third mechanism involves targeting the cryptocurrency Tether. While most cryptocurrencies have values that fluctuate with demand, Tether is a “stablecoin” that is supposedly backed one-to-one with dollars. Of course, it probably isn’t, as its claim to be the seventh largest holder of commercial paper (short-term loans to major businesses) is blatantly untrue. Instead, they appear part of a cycle where new Tether is issued, used to buy cryptocurrencies, and the resulting cryptocurrencies now “back” Tether and drive up the price.

This behavior is clearly that of a “wildcat bank,” an 1800s fraudulent banking style that has long been illegal. Tether also bears a striking similarity to Liberty Reserve, an online currency that the Department of Justice successfully prosecuted for money laundering in 2013. Shutting down Tether would have the side effect of eliminating the value proposition for the exchanges that support chain swapping, since these exchanges need a “stable” value for the speculators to trade against.

There are further possibilities. One involves treating the cryptocurrency miners, those who validate all transactions and add them to the public record, as money transmitters—and subject to the regulations around that business. Another option involves requiring cryptocurrency exchanges to actually deliver the cryptocurrencies into customer-controlled wallets.

Effectively, all cryptocurrency exchanges avoid transferring cryptocurrencies between customers. Instead, they simply record entries in a central database. This makes sense because actual “on chain” transactions can be particularly expensive for cryptocurrencies like bitcoin or Ethereum. If all speculators needed to actually receive their bitcoins, it would make clear that its value proposition as a currency simply doesn’t exist, as the already strained system would grind to a halt.

And, of course, law enforcement can already target criminals’ bitcoin directly. An example of this just occurred, when US law enforcement was able to seize 85% of the $4 million ransom Colonial Pipeline paid to the criminal organization DarkSide. That by the time the seizure occurred the bitcoin lost more than 30% of its value is just one more reminder of how unworkable bitcoin is as a “store of value.”

There is no single silver bullet to disrupt either cryptocurrencies or ransomware. But enough little disruptions, a “death of a thousand cuts” through new and existing regulation, should make bitcoin no longer usable for ransomware. And if there’s no safe way for a criminal to collect the ransom, their business model becomes no longer viable.

This essay was written with Nicholas Weaver, and previously appeared on Slate.com.

Posted on July 26, 2021 at 6:30 AMView Comments

The DarkSide Ransomware Gang

The New York Times has a long story on the DarkSide ransomware gang.

A glimpse into DarkSide’s secret communications in the months leading up to the Colonial Pipeline attack reveals a criminal operation on the rise, pulling in millions of dollars in ransom payments each month.

DarkSide offers what is known as “ransomware as a service,” in which a malware developer charges a user fee to so-called affiliates like Woris, who may not have the technical skills to actually create ransomware but are still capable of breaking into a victim’s computer systems.

DarkSide’s services include providing technical support for hackers, negotiating with targets like the publishing company, processing payments, and devising tailored pressure campaigns through blackmail and other means, such as secondary hacks to crash websites. DarkSide’s user fees operated on a sliding scale: 25 percent for any ransoms less than $500,000 down to 10 percent for ransoms over $5 million, according to the computer security firm, FireEye.

Posted on June 2, 2021 at 9:09 AMView Comments

Identifying the Person Behind Bitcoin Fog

The person behind the Bitcoin Fog was identified and arrested. Bitcoin Fog was an anonymization service: for a fee, it mixed a bunch of people’s bitcoins up so that it was hard to figure out where any individual coins came from. It ran for ten years.

Identifying the person behind Bitcoin Fog serves as an illustrative example of how hard it is to be anonymous online in the face of a competent police investigation:

Most remarkable, however, is the IRS’s account of tracking down Sterlingov using the very same sort of blockchain analysis that his own service was meant to defeat. The complaint outlines how Sterlingov allegedly paid for the server hosting of Bitcoin Fog at one point in 2011 using the now-defunct digital currency Liberty Reserve. It goes on to show the blockchain evidence that identifies Sterlingov’s purchase of that Liberty Reserve currency with bitcoins: He first exchanged euros for the bitcoins on the early cryptocurrency exchange Mt. Gox, then moved those bitcoins through several subsequent addresses, and finally traded them on another currency exchange for the Liberty Reserve funds he’d use to set up Bitcoin Fog’s domain.

Based on tracing those financial transactions, the IRS says, it then identified Mt. Gox accounts that used Sterlingov’s home address and phone number, and even a Google account that included a Russian-language document on its Google Drive offering instructions for how to obscure Bitcoin payments. That document described exactly the steps Sterlingov allegedly took to buy the Liberty Reserve funds he’d used.

Posted on May 3, 2021 at 9:36 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.