New Tricks of Cryptominers

Those familiar with the basic laws of economics know that a recession is often followed by growth. This natural cyclic pattern appears to hold true for the cryptocurrency markets as well. Having peaked at almost $20,000 in late 2017, Bitcoin’s price plummeted down to $4,000 in slightly more than a year’s time. What do we have now? Its value is quickly climbing back up, exceeding $11,000 as of early July 2019. Things look similarly auspicious for the other popular cryptocurrencies, too.

New Tricks of Cryptominers

Whilst this new boom is a benign signal for investors, it is also an “attack” command for cybercriminals. Malicious cryptomining also referred to as cryptojacking, is at the core of all abuse in this ecosystem. To set this exploitation in motion, crooks deposit malware onto hosts in order to parasitize the processing power and thereby mine coins behind the victims’ backs. This incursion vector continues to be the case, but the hackers’ tactics have changed over time. Below are several examples of how sophisticated the present-day cryptojacking has become.

Malware making Linux cryptominer cross-platform

In a large-scale campaign that surfaced in late June 2019, perpetrators have been utilizing the malicious code to inject and run a well-known Monero CPU miner called XMRig on host computers. Although these attacks leverage a Linux variant of the miner, a clever trick allows the malefactors to deploy it on Windows and macOS systems. Instead of reinventing the wheel, they use virtualization software to execute the XMRig instance on machines regardless of the operating system.

The malware underlying this hoax is codenamed LoudMiner. It arrives with cracked VST (Virtual Studio Technology) applications. Researchers from ESET found more than a hundred booby-trapped solutions from this category that go bundled with the harmful payload in question. Most of them are tailored for macOS. VST apps tend to be resource heavy, so they are typically installed on powerful systems with plenty of CPU capacity to quench the attackers’ thirst for easy gain.

The furtive cryptocurrency mining process is performed on the Tiny Core Linux virtual machine. The total size of the XMRig and virtual machine combo can be greater than 100 MB. However, the victims are likely to overlook it being dropped by the LoudMiner malware, given that VST workstations typically have a lot of disk space under the hood.

The offending code establishes persistence on a host by invoking commands to make sure the Monero miner’s Linux image is launched at boot time and automatically restarted if terminated. On Macs, the infection can hide its shenanigans by pausing the surreptitious mining routine whenever the user opens the Activity Monitor. All in all, this raid may stay undetected for a long time and siphon off the hosts’ hefty processing potential to mine Monero for the ill-minded operators.

Persistence quirk of a cryptominer

Analysts from cybersecurity firm Sucuri have recently spotted a sample of coin mining malware that re-infects hosts even after being removed. The culprit zeroes in on 32- and 64-bit Linux installations, both servers and desktop machines. It was originally found on a web server whose CPU was running at its maximum, which is a telltale sign of cryptomining activity without any throttling in effect.

According to the researchers’ findings, the black hats utilize a Bash script that silently downloads the final-stage payload. It isn’t entirely clear how exactly this script ends up inside a target system, but the most likely entry point is an unpatched software flaw or credentials brute-forcing.

When first launched, the Bash script named performs a series of checks to find any instances of known cryptomining processes already running. If detected, these tasks are subject to instant termination. The next phase is to download the actual coin miner from the attackers’ command and control server. What makes the pest really stand out, though, is that it creates a cron job to check for the initial Bash script every minute. If it’s missing, the scheduled task will download and run it on the compromised system again. This way, the attack perseveres even if the user identifies the threat and eradicates all the troublemaking components from the host.

Multipronged cryptominer with backdoor and worm characteristics

A sophisticated strain of coin mining malware dubbed Plurox popped up on Kaspersky Lab’s radar in February 2019. Unlike garden-variety infections from this category, it behaves like a backdoor and has a modular nature. The former trait means that Plurox creates a loophole so that the attackers can access a compromised network at any time, and the latter feature allows for enhancements of the malicious functionality by means of specially crafted plugins.

On top of that, the malware was found to employ distribution mechanisms inherent to computer worms. Having hit one host, it can quickly pollute the entire LAN by abusing SMB (Server Message Block) and UPnP (Universal Plug and Play) protocols. Plurox adds the notorious NSA exploit called EternalBlue to the self-spreading mix as it downloads a dodgy SMB plugin from its C2 server. A shady UPnP plugin, in its turn, uses a port forwarding trick to infect other machines on the same network.

As soon as Plurox contaminates a host, it gathers details regarding the hardware configuration, and based on that, requests an appropriate cryptocurrency mining plugin from its command and control. The malware communicates with the server over the TCP protocol. The analysts discovered a total of eight downloadable modules intended for the mining job on computers with different processing capabilities. Furthermore, the harmful code can update, stop, and delete its plugins behind the scenes.

Plurox is undoubtedly one of today’s most complex cryptomining menaces out there. Researchers believe it is still a work in progress, judging from multiple debug lines found in its code. Therefore, as if the current deleterious features weren’t enough, it might be equipped with additional characteristics in the near future.

The bottom line

A recent trend in the wicked cryptomining world is the rise of Linux malware designed to drain the infected systems’ processing power in the background. These perils mostly target servers and high-end computers that can yield better and faster results for the crooks. It’s also worth mentioning that stealthy cryptominers are becoming harder to detect and remove, so the security community has yet to come up with an effective response for these disconcerting evolutionary changes. In the meanwhile, regular users and server owners should keep tabs on the CPU consumption by their machines. Regular system updates, best antimalware tools, reliable VPNs and strong passwords should also help.

Check the comment section below for additional information, share what you know, or ask a question about this article by leaving a comment below. And, to quickly find answers to your questions, use our search Search engine.

Note: Some of the information in samples on this website may have been impersonated or spoofed.

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Online Threat Alerts Security Tips

Pay the safest way

Credit cards are the safest way to pay for online purchases because you can dispute the charges if you never get the goods or services or if the offer was misrepresented. Federal law limits your liability to $50 if someone makes unauthorized charges to your account, and most credit card issuers will remove them completely if you report the problem promptly.

Guard your personal information

In any transaction you conduct, make sure to check with your state or local consumer protection agency and the Better Business Bureau (BBB) to see if the seller, charity, company, or organization is credible. Be especially wary if the entity is unfamiliar to you. Always call the number found on a website’s contact information to make sure the number legitimately belongs to the entity you are dealing with.

Be careful of the information you share

Never give out your codes, passwords or personal information, unless you are sure of who you're dealing with

Know who you’re dealing with

Crooks pretending to be from companies you do business with may call or send an email, claiming they need to verify your personal information. Don’t provide your credit card or bank account number unless you are actually paying for something and know who you are sending payment to. Your social security number should not be necessary unless you are applying for credit. Be especially suspicious if someone claiming to be from a company with whom you have an account asks for information that the business already has.

Check your accounts

Regularly check your account transactions and report any suspicious or unauthorised transactions.

Don’t believe promises of easy money

If someone claims that you can earn money with little or no work, get a loan or credit card even if you have bad credit, or make money on an investment with little or no risk, it’s probably a scam. Oftentimes, offers that seem too good to be true, actually are too good to be true.

Do not open email from people you don’t know

If you are unsure whether an email you received is legitimate, try contacting the sender directly via other means. Do not click on any links in an email unless you are sure it is safe.

Think before you click

If an email or text message looks suspicious, don’t open any attachments or click on the links.

Verify urgent requests or unsolicited emails, messages or phone calls before you respond

If you receive a message or a phone call asking for immediate action and don't know the sender, it could be a phishing message.

Be careful with links and new website addresses

Malicious website addresses may appear almost identical to legitimate sites. Scammers often use a slight variation in spelling or logo to lure you. Malicious links can also come from friends whose email has unknowingly been compromised, so be careful.

Secure your personal information

Before providing any personal information, such as your date of birth, Social Security number, account numbers, and passwords, be sure the website is secure.

Stay informed on the latest cyber threats

Keep yourself up to date on current scams by visiting this website daily.

Use Strong Passwords

Strong passwords are critical to online security.

Keep your software up to date and maintain preventative software programs

Keep all of your software applications up to date on your computers and mobile devices. Install software that provides antivirus, firewall, and email filter services.

Update the operating systems on your electronic devices

Make sure your operating systems (OSs) and applications are up to date on all of your electronic devices. Older and unpatched versions of OSs and software are the target of many hacks. Read the CISA security tip on Understanding Patches and Software Updates for more information.

What if You Got Scammed?

Stop Contact With The Scammer

Hang up the phone. Do not reply to emails, messages, or letters that the scammer sends. Do not make any more payments to the scammer. Beware of additional scammers who may contact you claiming they can help you get your lost money back.

Secure Your Finances

  • Report potentially compromised bank account, credit or debit card information to your financial institution(s) immediately. They may be able to cancel or reverse fraudulent transactions.
  • Notify the three major credit bureaus. They can add a fraud alert to warn potential credit grantors that you may be a victim of identity theft. You may also want to consider placing a free security freeze on your credit report. Doing so prevents lenders and others from accessing your credit report entirely, which will prevent them from extending credit:

Check Your Computer

If your computer was accessed or otherwise affected by a scam, check to make sure that your anti-virus is up-to-date and running and that your system is free of malware and keylogging software. You may also need to seek the help of a computer repair company. Consider utilizing the Better Business Bureau’s website to find a reputable company.

Change Your Account Passwords

Update your bank, credit card, social media, and email account passwords to try to limit further unauthorized access. Make sure to choose strong passwords when changing account passwords.

Report The Scam

Reporting helps protect others. While agencies can’t always track down perpetrators of crimes against scammers, they can utilize the information gathered to record patterns of abuse which may lead to action being taken against a company or industry.

Report your issue to the following agencies based on the nature of the scam:

  • Local Law Enforcement: Consumers are encouraged to report scams to their local police department or sheriff’s office, especially if you lost money or property or had your identity compromised.
  • Federal Trade Commission: Contact the Federal Trade Commission (FTC) at 1-877-FTC-HELP (1-877-382-4357) or use the Online Complaint Assistant to report various types of fraud, including counterfeit checks, lottery or sweepstakes scams, and more.
  • If someone is using your personal information, like your Social Security, credit card, or bank account number, to open new accounts, make purchases, or get a tax refund, report it at This federal government site will also help you create your Identity Theft Report and a personal recovery plan based on your situation. Questions can be directed to 877-ID THEFT.

How To Recognize a Phishing Scam

Scammers use email or text messages to try to steal your passwords, account numbers, or Social Security numbers. If they get that information, they could get access to your email, bank, or other accounts. Or they could sell your information to other scammers. Scammers launch thousands of phishing attacks like these every day — and they’re often successful.

Scammers often update their tactics to keep up with the latest news or trends, but here are some common tactics used in phishing emails or text messages:

Phishing emails and text messages often tell a story to trick you into clicking on a link or opening an attachment. You might get an unexpected email or text message that looks like it’s from a company you know or trust, like a bank or a credit card or utility company. Or maybe it’s from an online payment website or app. The message could be from a scammer, who might

  • say they’ve noticed some suspicious activity or log-in attempts — they haven’t
  • claim there’s a problem with your account or your payment information — there isn’t
  • say you need to confirm some personal or financial information — you don’t
  • include an invoice you don’t recognize — it’s fake
  • want you to click on a link to make a payment — but the link has malware
  • say you’re eligible to register for a government refund — it’s a scam
  • offer a coupon for free stuff — it’s not real

About Online Threat Alerts (OTA)

Online Threat Alerts or OTA is an anti-cybercrime community that started in 2012. OTA alerts the public to cyber crimes and other web threats.

By alerting the public, we have prevented a lot of online users from getting scammed or becoming victims of cybercrimes.

With the ever-increasing number of people going online, it important to have a community like OTA that continuously alerts or protects those same people from cyber-criminals, scammers and hackers, who are every day finding new ways of carrying out their malicious activities.

Online users can help by reporting suspicious or malicious messages or websites to OTA. And, if they want to determine if a message or website is a threat or scam, they can use OTA's search engine to search for the website or parts of the message for information.

Help maintain Online Threat Alerts (OTA).

New Tricks of Cryptominers