ST18-002: Defending Against Illicit Cryptocurrency Mining Activity

["US-CERT" <US-CERT () ncas us-cert gov>]

U.S. Department of Homeland Security US-CERT

National Cyber Awareness System:



ST18-002: Defending Against Illicit Cryptocurrency Mining Activity [ https://www.us-cert.gov/ncas/tips/ST18-002 ] 
06/26/2018 02:57 PM EDT 
Original release date: June 26, 2018

The popularity of cryptocurrency, a form of digital currency, is rising; Bitcoin, Litecoin, Monero, Ethereum, and 
Ripple are just a few types of the cryptocurrencies available. Though cryptocurrency is a common topic of conversation, 
many people lack a basic understanding of cryptocurrency and the risks associated with it. This lack of awareness is 
contributing to the rise of individuals and organizations falling victim to illicit cryptocurrency mining activity.

What is cryptocurrency?

Cryptocurrency is a digital currency used as a medium of exchange, similar to other currencies. However, unlike other 
currencies, cryptocurrency operates independently of a central bank and uses encryption techniques and blockchain 
technology to secure and verify transactions.

What is cryptomining?

Cryptocurrency mining, or cryptomining, is simply the way in which cryptocurrency is earned. Individuals mine 
cryptocurrency by using cryptomining software to solve complex mathematical problems involved in validating 
transactions. Each solved equation verifies a transaction and earns a reward paid out in the cryptocurrency. Solving 
cryptographic calculations to mine cryptocurrency requires a massive amount of processing power.

What is cryptojacking?

Cryptojacking occurs when malicious cyber actors exploit vulnerabilitiesin webpages, software, and operating systemsto 
illicitly install cryptomining software on victim devices and systems. With the cryptomining software installed, the 
malicious cyber actors effectively hijack the processing power of the victim devices and systems to earn 
cryptocurrency. Additionally, malicious cyber actors may infect a website with cryptomining JavaScript code, which 
leverages a visitors processing power via their browser to mine cryptocurrency. Cryptojacking may result in the 
following consequences to victim devices, systems, and networks:


  * Degraded system and network performance because bandwidth and central processing unit (CPU) resources are 
monopolized by cryptomining activity; 
  * Increased power consumption, system crashes, and potential physical damage from component failure due to the 
extreme temperatures caused by cryptomining; 
  * Disruption of regular operations; and 
  * Financial loss due to system downtime caused by component failure and the cost of restoring systems and files to 
full operation as well as the cost of the increased power consumption. 

Cryptojacking involves maliciously installed programs that are persistent or non-persistent. Non-persistent 
cryptojacking usually occurs only while a user is visiting a particular webpage or has an internet browser open. 
Persistent cryptojacking continues to occur even after a user has stopped visiting the source that originally caused 
their system to perform mining activity.

Malicious actors distribute cryptojacking malware through weaponized mobile applications, botnets, and social media 
platforms by exploiting flaws in applications and servers, and by hijacking Wi-Fi hotspots.

What types of systems and devices are at risk for cryptojacking?

Any internet-connected device with a CPU is susceptible to cryptojacking. The following are commonly targeted devices:


  * *Computer systems and network devices * including those connected to information technology and Industrial Control 
System networks; 
  * *Mobile devices * devices are subject to the same vulnerabilities as computers; and 
  * *Internet of Things devices * internet-enabled devices (e.g., printers, video cameras, and smart TVs). 

How do you defend against cryptojacking?

The following cybersecurity best practices can help you protect your internet-connected systems and devices against 
cryptojacking:


  * *Use and maintain antivirus software*. Antivirus software recognizes and protects a computer against malware, 
allowing the owner or operator to detect and remove a potentially unwanted program before it can do any damage. (See 
Understanding Anti-Virus Software [ https://www.us-cert.gov/ncas/tips/st04-005 ].) 
  * *Keep software and operating systems up-to-date*. Install software updates so that attackers cannot take advantage 
of known problems or vulnerabilities. (See Understanding Patches [ https://www.us-cert.gov/ncas/tips/st04-006 ].) 
  * *Use strong passwords*. Select passwords that will be difficult for attackers to guess, and use different passwords 
for different programs and devices. It is best to use long, strong passphrases or passwords that consist of at least 16 
characters. (See Choosing and Protecting Passwords [ https://www.us-cert.gov/ncas/tips/ST04-002 ].) 
  * *Change default usernames and passwords*. Default usernames and passwords are readily available to malicious 
actors. Change default passwords, as soon as possible, to a sufficiently strong and unique password. 
  * *Check system privilege policies*. Review user accounts and verify that users with administrative rights have a 
need for those privileges. Restrict general user accounts from performing administrative functions. 
  * *Apply application whitelisting*. Consider using application whitelists to prevent unknown executables from 
launching autonomously. 
  * *Be wary of downloading files from websites*. Avoid downloading files from untrusted websites. Look for an 
authentic website certificate when downloading files from a secure site. (See Understanding Web Site Certificates [ 
https://www.us-cert.gov/ncas/tips/st05-010 ].) 
  * *Recognize normal CPU activity and monitor for abnormal activity*. Network administrators should continuously 
monitor systems and educate their employees to recognize any above-normal sustained CPU activity on computer 
workstations, mobile devices, and network servers. Any noticeable degradation in processing speed requires 
investigation. 
  * *Disable unnecessary services*. Review all running services and disable those that are unnecessary for operations. 
Disabling or blocking some services may create problems by obstructing access to files, data, or devices. 
  * *Uninstall unused software*. Review installed software applications and remove those not needed for operations. 
Many retail computer systems with pre-loaded operating systems come with toolbars, games, and adware installed, all of 
which can use excessive disk space and memory. These unnecessary applications can provide avenues for attackers to 
exploit a system. 
  * *Validate input*. Perform input validation on internet-facing web server and web applications to mitigate injection 
attacks. On web browsers, disable JavaScript execution. For Microsoft Internet Explorer, enable the cross-site 
scripting filter. 
  * *Install a firewall*. Firewalls may be able to prevent some types of attack vectors by blocking malicious traffic 
before it can enter a computer system, and by restricting unnecessary outbound communications. Some device operating 
systems include a firewall. Enable and properly configure the firewall as specified in the device or system owners 
manual. (See Understanding Firewalls [ https://www.us-cert.gov/ncas/tips/st04-004 ].) 
  * *Create and monitor blacklists*. Monitor industry reports of websites that are hosting, distributing, and being 
used for, malware command and control. Block the internet protocol addresses of known malicious sites to prevent 
devices from being able to access them. 
________________________________________________________________________

Author: NCCIC________________________________________________________________________

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