Entries Tagged "ransomware"

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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 AM • View Comments

REvil is Off-Line

This is an interesting development:

Just days after President Biden demanded that President Vladimir V. Putin of Russia shut down ransomware groups attacking American targets, the most aggressive of the groups suddenly went off-line early Tuesday.

[…]

Gone was the publicly available “happy blog” the group maintained, listing some of its victims and the group’s earnings from its digital extortion schemes. Internet security groups said the custom-made sites ­- think of them as virtual conference rooms—where victims negotiated with REvil over how much ransom they would pay to get their data unlocked also disappeared. So did the infrastructure for making payments.

Okay. So either the US took them down, Russia took them down, or they took themselves down.

Posted on July 16, 2021 at 3:03 PM • View Comments

Details of the REvil Ransomware Attack

ArsTechnica has a good story on the REvil ransomware attack of last weekend, with technical details:

This weekend’s attack was carried out with almost surgical precision. According to Cybereason, the REvil affiliates first gained access to targeted environments and then used the zero-day in the Kaseya Agent Monitor to gain administrative control over the target’s network. After writing a base-64-encoded payload to a file named agent.crt the dropper executed it.

[…]

The ransomware dropper Agent.exe is signed with a Windows-trusted certificate that uses the registrant name “PB03 TRANSPORT LTD.” By digitally signing their malware, attackers are able to suppress many security warnings that would otherwise appear when it’s being installed. Cybereason said that the certificate appears to have been used exclusively by REvil malware that was deployed during this attack.

To add stealth, the attackers used a technique called DLL Side-Loading, which places a spoofed malicious DLL file in a Windows’ WinSxS directory so that the operating system loads the spoof instead of the legitimate file. In the case here, Agent.exe drops an outdated version that is vulnerable to DLL Side-Loading of “msmpeng.exe,” which is the file for the Windows Defender executable.

Once executed, the malware changes the firewall settings to allow local windows systems to be discovered. Then, it starts to encrypt the files on the system….

REvil is demanding $70 million for a universal decryptor that will recover the data from the 1,500 affected Kaseya customers.

More news.

Note that this is yet another supply-chain attack. Instead of infecting those 1,500 networks directly, REvil infected a single managed service provider. And it leveraged a zero-day vulnerability in that provider.

EDITED TO ADD (7/13): Employees warned Kaseya’s management for years about critical security flaws, but they were ignored.

Posted on July 8, 2021 at 10:06 AM • View Comments

Insurance and Ransomware

As ransomware becomes more common, I’m seeing more discussions about the ethics of paying the ransom. Here’s one more contribution to that issue: a research paper that the insurance industry is hurting more than it’s helping.

However, the most pressing challenge currently facing the industry is ransomware. Although it is a societal problem, cyber insurers have received considerable criticism for facilitating ransom payments to cybercriminals. These add fuel to the fire by incentivising cybercriminals’ engagement in ransomware operations and enabling existing operators to invest in and expand their capabilities. Growing losses from ransomware attacks have also emphasised that the current reality is not sustainable for insurers either.

To overcome these challenges and champion the positive effects of cyber insurance, this paper calls for a series of interventions from government and industry. Some in the industry favour allowing the market to mature on its own, but it will not be possible to rely on changing market forces alone. To date, the UK government has taken a light-touch approach to the cyber insurance industry. With the market undergoing changes amid growing losses, more coordinated action by government and regulators is necessary to help the industry reach its full potential.

The interventions recommended here are still relatively light, and reflect the fact that cyber insurance is only a potential incentive for managing societal cyber risk.They include: developing guidance for minimum security standards for underwriting; expanding data collection and data sharing; mandating cyber insurance for government suppliers; and creating a new collaborative approach between insurers and intelligence and law enforcement agencies around ransomware.

Finally, although a well-functioning cyber insurance industry could improve cyber security practices on a societal scale, it is not a silver bullet for the cyber security challenge. It is important to remember that the primary purpose of cyber insurance is not to improve cyber security, but to transfer residual risk. As such, it should be one of many tools that governments and businesses can draw on to manage cyber risk more effectively.

Basically, the insurance industry incents companies to do the cheapest mitigation possible. Often, that’s paying the ransom.

News article.

Posted on July 1, 2021 at 11:01 AM • View 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 AM • View Comments

New Disk Wiping Malware Targets Israel

Apostle seems to be a new strain of malware that destroys data.

In a post published Tuesday, SentinelOne researchers said they assessed with high confidence that based on the code and the servers Apostle reported to, the malware was being used by a newly discovered group with ties to the Iranian government. While a ransomware note the researchers recovered suggested that Apostle had been used against a critical facility in the United Arab Emirates, the primary target was Israel.

Posted on May 26, 2021 at 9:33 AM • View Comments

Double-Encrypting Ransomware

This seems to be a new tactic:

Emsisoft has identified two distinct tactics. In the first, hackers encrypt data with ransomware A and then re-encrypt that data with ransomware B. The other path involves what Emsisoft calls a “side-by-side encryption” attack, in which attacks encrypt some of an organization’s systems with ransomware A and others with ransomware B. In that case, data is only encrypted once, but a victim would need both decryption keys to unlock everything. The researchers also note that in this side-by-side scenario, attackers take steps to make the two distinct strains of ransomware look as similar as possible, so it’s more difficult for incident responders to sort out what’s going on.

Posted on May 21, 2021 at 8:50 AM • View Comments

Adding a Russian Keyboard to Protect against Ransomware

A lot of Russian malware—the malware that targeted the Colonial Pipeline, for example—won’t install on computers with a Cyrillic keyboard installed. Brian Krebs wonders if this could be a useful defense:

In Russia, for example, authorities there generally will not initiate a cybercrime investigation against one of their own unless a company or individual within the country’s borders files an official complaint as a victim. Ensuring that no affiliates can produce victims in their own countries is the easiest way for these criminals to stay off the radar of domestic law enforcement agencies.

[…]

DarkSide, like a great many other malware strains, has a hard-coded do-not-install list of countries which are the principal members of the Commonwealth of Independent States (CIS)—former Soviet satellites that mostly have favorable relations with the Kremlin.

[…]

Simply put, countless malware strains will check for the presence of one of these languages on the system, and if they’re detected the malware will exit and fail to install.

[…]

Will installing one of these languages keep your Windows computer safe from all malware? Absolutely not. There is plenty of malware that doesn’t care where in the world you are. And there is no substitute for adopting a defense-in-depth posture, and avoiding risky behaviors online.

But is there really a downside to taking this simple, free, prophylactic approach? None that I can see, other than perhaps a sinking feeling of capitulation. The worst that could happen is that you accidentally toggle the language settings and all your menu options are in Russian.

EDITED TO ADD (6/14): According to some, this doesn’t work.

Posted on May 18, 2021 at 10:31 AM • View Comments

Ransomware Is Getting Ugly

Modern ransomware has two dimensions: pay to get your data back, and pay not to have your data dumped on the Internet. The DC police are the victims of this ransomware, and the criminals have just posted personnel records—”including the results of psychological assessments and polygraph tests; driver’s license images; fingerprints; social security numbers; dates of birth; and residential, financial, and marriage histories”—for two dozen police officers.

The negotiations don’t seem to be doing well. The criminals want $4M. The DC police offered them $100,000.

The Colonial Pipeline is another current high-profile ransomware victim. (Brian Krebs has some good information on DarkSide, the criminal group behind that attack.) So is Vastaamo, a Finnish mental heal clinic. Criminals contacted the individual patients and demanded payment, and then dumped their personal psychological information online.

An industry group called the Institute for Security and Technology (no, I haven’t heard of it before, either) just released a comprehensive report on combating ransomware. It has a “comprehensive plan of action,” which isn’t much different from anything most of us can propose. Solving this is not easy. Ransomware is big business, made possible by insecure networks that allow criminals to gain access to networks in the first place, and cryptocurrencies that allow for payments that governments cannot interdict. Ransomware has become the most profitable cybercrime business model, and until we solve those two problems, that’s not going to change.

Posted on May 14, 2021 at 6:30 AM • View Comments

Ransomware Shuts Down US Pipeline

This is a major story: a probably Russian cybercrime group called DarkSide shut down the Colonial Pipeline in a ransomware attack. The pipeline supplies much of the East Coast. This is the new and improved ransomware attack: the hackers stole nearly 100 gig of data, and are threatening to publish it. The White House has declared a state of emergency and has created a task force to deal with the problem, but it’s unclear what they can do. This is bad; our supply chains are so tightly coupled that this kind of thing can have disproportionate effects.

EDITED TO ADD (5/12): It seems that the billing system was attacked, and not the physical pipeline itself.

Posted on May 10, 2021 at 2:17 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.