What is Crypto Ransomware?

Crypto ransomware — also known as crypto-malware is malware that encrypts files on a device and demands a ransom for its recovery. Victims are incentivized to pay the ransom because only the cybercriminals behind the attack know the decryption key needed to recover their data.

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How Does Crypto Ransomware Work?

A ransomware attack is a multi-stage process including everything from initial access to demanding a ransom payment. Some of the key steps include the following:

Infection Methods

To encrypt files, ransomware needs access to the files on a victim’s machine. Some common attack vectors include the following:

  • Phishing Emails: Phishing emails use social engineering to trick the recipient into installing the malware. The emails might have attachments infected with malware or include malicious links that point to infected web pages.
  • Malicious Websites: Websites may have malware available for download. Often, this involves a trojan horse, which is malware that pretends to be legitimate software but actually infects the user’s computer.
  • Compromised Accounts: Ransomware operators may also deploy malware using compromised user accounts. If a password is guessed or breached, the attacker can log in via RDP or VPN to plant their malware on corporate systems.

Encryption Process

Most ransomware uses a combination of symmetric and asymmetric encryption algorithms.

 

Symmetric encryption is highly efficient for bulk encryption. Ransomware uses it to encrypt files and deny their owners access to them. Asymmetric encryption is used to protect the symmetric encryption keys. If the public key is bundled with the malware, the ransomware can encrypt and store the symmetric encryption key alongside the encrypted files. The attackers keep only copy of the private key and can use it to decrypt the symmetric key once the victim has paid the ransom.

 

Ransomware’s encryption process has also evolved. For example, some ransomware variants will only encrypt part of a file. This enables the encryption process to occur more quickly — decreasing the risk of interruption — while still rendering the files unusable.

Ransom Notes and Demands

 

After file encryption is complete, the ransomware will display ransom notes to the victim. These typically inform the victim that they’ve been infected with ransomware and provide information on how the ransom should be paid.

Payment in Cryptocurrency

 

Crypto ransomware uses cryptocurrency for payments. If the victim elects to pay the ransom, they will purchase cryptocurrency and transfer it to the attacker’s account, whose address is likely included in the ransom note. Then, the attacker should provide a decryptor that can be used to restore the victim’s encrypted files.

Examples of Crypto Ransomware

Many cybercrime groups have emerged and begun distributing ransomware. Some of the currently largest ransomware groups include LockBit, Alphv/BlackCat, CL0P, Black Basta, Play, Royal, 8Base, BianLian, Medusa, and NoEscape.

Why Cryptocurrencies are Used for Ransom Payments

Cryptocurrencies are used for ransom payments for a few different reasons. The primary one is that they’re pseudonymous and not affiliated with the central banking system. Users’ cryptocurrency accounts aren’t linked to their real-world identity unless they go through an exchange that requires Know Your Customer (KYC). As a result, it can be difficult to trace a cryptocurrency payment to its recipient, protecting the attacker against detection.

How to Prevent Crypto Ransomware Attacks

Crypto malware attacks can be devastating for an organization. Some best practices for preventing these attacks include the following:

  • User Education: Many ransomware attacks target users with phishing attacks. Cybersecurity education can help users to identify and avoid falling for these attacks.
  • Data Backups: Ransomware operations extort ransom payments by encrypting data and rendering it inaccessible to its owners. The ability to restore from backups can eliminate the need to pay the ransom.
  • Patching: Some ransomware variants exploit vulnerable software to infect computers. Performing regular patching and updates can help to fix these issues before they can be exploited by malware.
  • Strong Authentication: Some crypto malware uses compromised user accounts to access and infect corporate systems. To help manage this risk, implement strong user authentication — including multi-factor authentication (MFA).
  • Anti-Ransomware Solutions: Anti-ransomware solutions can detect and block crypto ransomware before it reaches an organization’s systems. This helps to limit the risk to the business and its data.

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Ransomware has emerged as a leading threat to businesses due to the potential for lost data and significant financial losses for an organization. To learn more about how to manage your organization’s exposure to this threat, check out the CISO Guide to Ransomware Prevention.

Check Point’s Harmony Endpoint protects organizations against ransomware and other threats, including those outlined in the Cyber Security Report. To learn how Harmony Endpoint can help strengthen your organization’s endpoint security, register for a free demo today.

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