Decrypting Ransomware: Understanding How Cybercriminals Hold Your Data Hostage

Ransomware is malicious software that encrypts a victim’s files or locks their systems and demands a ransom payment in exchange for the decryption key. It has emerged as one of the most financially damaging cyberattack categories, with consequences that include loss of critical data, operational shutdowns, ransom demands ranging from thousands to tens of millions of dollars, and recovery costs that frequently exceed the ransom amount. Understanding how ransomware attacks work and building the technical and organizational controls to prevent and respond to them is essential for any organization that stores or processes sensitive data. The recommended action: implement code signing validation to block malicious executables, maintain tested offline backups, enforce MFA on all remote access and email accounts, and build a ransomware-specific track in your incident response plan. For the broader incident response framework, see Build A Secure Incident Response Plan For Your Organization. For code signing integrity controls, see CodeSign Secure.

Quick Answer: What Is Ransomware and How Does It Work?

Ransomware is malicious software that gains access to a victim’s systems, encrypts files or locks the system, and demands a ransom payment in exchange for the decryption key. It typically follows a three-step process: gaining initial access through phishing emails, compromised software, or vulnerable internet-facing services; encrypting data using hybrid encryption schemes that combine fast symmetric encryption of victim data with asymmetric protection of the symmetric key; and demanding payment in cryptocurrency in exchange for the key required to decrypt the data. Paying the ransom does not guarantee decryption, does not prevent additional ransom demands, and does not prevent the attacker from publishing any exfiltrated data.

Ransomware Attacks and Their Process

Ransomware attacks typically follow a three-step process: gaining access, encrypting data, and demanding a ransom. The first step, gaining access, can be accomplished through various means. Phishing emails are the most common initial access vector: attackers send messages designed to trick recipients into clicking a malicious link or opening an infected attachment. Other access methods include compromised software with malicious payloads, peer-to-peer file sharing networks, USB drives intentionally left in public locations, and fraudulent websites designed to resemble legitimate brands. Attackers also exploit unpatched vulnerabilities in internet-facing services including VPNs, remote desktop protocol (RDP), and web applications to gain direct access without requiring user interaction.

Once the attacker gains access to the target system, they proceed to encrypt valuable data including personal details, credit card information, account credentials, and operational files. Modern ransomware employs hybrid encryption schemes, combining symmetric encryption to encrypt the actual data quickly with asymmetric encryption to protect the symmetric key. The symmetric key is encrypted with the attacker’s public key, meaning only the attacker’s corresponding private key can decrypt it. This design ensures that even if a victim identifies the ransomware’s symmetric key in memory before encryption completes, it cannot be used to decrypt the data without the attacker’s private key.

After encrypting the data, the attacker demands a ransom to release the private key required for decryption. Ransoms are typically demanded in cryptocurrencies such as Bitcoin or Monero, which provide a degree of pseudonymity. Attackers often set deadlines and escalating demands to create pressure. It is important to note that paying the ransom does not guarantee the release of a working decryption key, does not prevent additional ransom demands, and funds criminal operations that enable future attacks. Starting approximately in 2019, many ransomware groups adopted double-extortion: encrypting files while also exfiltrating data, and threatening to publish the stolen data if the ransom is not paid, giving them leverage even against organizations with clean backups.

Notable Ransomware Variants and Attacks

Numerous ransomware variants have caused significant damage and financial losses over the years. Understanding their tactics provides practical context for detection and prevention. Some of the most operationally significant ransomware strains include:

Ransomware Variant	Notable Characteristic	Primary Attack Vector
WannaCry	Worm capability allowed self-propagation across networks without user interaction; affected organizations in over 150 countries in May 2017	EternalBlue exploit targeting unpatched SMB vulnerability (MS17-010)
NotPetya	Classified by multiple governments as a destructive cyberweapon rather than ransomware; designed to cause damage rather than enable decryption	Compromised software update mechanism; spread via EternalBlue
REvil (Sodinokibi)	Operated as Ransomware-as-a-Service (RaaS); responsible for numerous high-profile attacks; operated a leak site threatening data publication	Phishing, RDP exploitation, zero-day vulnerabilities
Maze	Pioneer of double-extortion: first prominent group to combine file encryption with data theft and public leak threats	Phishing, exploit kits, RDP
LockBit	Highly prolific RaaS group; responsible for attack on Entrust Corporation in 2022; maintained a countdown leak site	Phishing, compromised credentials, unpatched vulnerabilities
DoppelPaymer, Kronos, MedusaLocker, NetWalker, GandCrab, TeslaCrypt, SamSam	Various RaaS and targeted ransomware strains that collectively caused billions in damages across healthcare, government, and enterprise targets	Varied; phishing, RDP, compromised software

In 2022, notable ransomware attacks occurred against prominent organizations. An attack targeted Nvidia, the graphics processing unit manufacturer, with the Lapsus$ group claiming responsibility and stating that they had access to employee information and had seized significant data. A separate attack was aimed at Entrust Corporation, a digital security company. The LockBit ransomware group carried out the attack and created a dedicated leak site displaying a countdown timer for the release of customer data. Despite the attack, Entrust refused to pay the ransom. For the code signing security dimensions of the Nvidia breach, see Nvidia Code Signing Certificates Stolen by Ransomware Group.

Detection Actions: How to Identify a Ransomware Attack in Progress

Early detection is the most important factor in limiting ransomware damage. Ransomware encryption takes time, and most attacks can be stopped before completion if detected quickly. Key detection signals include:

• Unusual file system activity: mass file renaming, extension changes, or large numbers of file write operations occurring rapidly across network shares
• Unexpected encryption process creation: new processes with high CPU or disk I/O activity that do not correspond to scheduled tasks or known applications
• Backup deletion or shadow copy removal: ransomware routinely deletes Volume Shadow Copies and backup files to prevent recovery without paying the ransom
• Unusual outbound network connections: communication with attacker-controlled command and control (C2) servers before encryption begins, often used to transmit the symmetric encryption key
• Antivirus or EDR alerts: modern endpoint detection tools recognize behavioral patterns associated with ransomware such as rapid file encryption, shadow copy deletion, and process injection
• Unusual administrative credential use: many ransomware attacks involve lateral movement using stolen or compromised administrative credentials before encryption begins

The Role of Encryption Consulting in Ransomware Prevention

To protect against ransomware attacks and strengthen overall cybersecurity, organizations can seek assistance from Encryption Consulting. Encryption Consulting specializes in data protection, Public Key Infrastructure (PKI), and Hardware Security Modules (HSMs). We offer CodeSign Secure, a comprehensive tool for code signing files, which helps organizations ensure that no malicious code is injected into their software. Code signing mitigates the risks associated with compromised software and malicious updates by enabling verification that executables come from a trusted publisher and have not been modified since signing. If attackers steal code signing certificates (as demonstrated in the Nvidia breach), the private key theft itself becomes a critical incident requiring immediate response. For private key protection, FIPS 140-3 validated HSMs provide the tamper-resistant storage and access controls that prevent private key extraction even by insiders.

Ransomware Remediation Checklist

Use this checklist during and after a ransomware incident to ensure containment, eradication, and recovery are complete:

• Isolate affected systems from the network immediately to prevent lateral spread; do not shut down (preserves volatile memory for forensics)
• Identify the ransomware variant from ransom notes, encrypted file extensions, and behavioral indicators to determine if a decryptor is available from law enforcement resources
• Verify backup integrity before beginning recovery; confirm backups are clean and predate the infection
• Revoke and rotate all credentials that may have been exposed on affected systems; treat all credentials on affected systems as compromised
• If code signing certificates or private keys were accessible on affected systems, initiate certificate revocation and key replacement immediately
• Notify relevant internal stakeholders including legal counsel, HR, communications, and executive leadership
• Assess regulatory notification obligations triggered by the incident (HIPAA, PCI DSS, GDPR, state breach notification laws)
• Do not pay the ransom without consulting legal counsel; document the decision-making process regardless of outcome
• Preserve forensic evidence including memory images, log files, and ransom notes before remediation activities that might overwrite evidence
• Patch the vulnerability or access vector used for initial access before reconnecting recovered systems to the network
• Conduct a post-incident review and update the incident response plan with lessons learned

Conclusion

Ransomware attacks have become increasingly prevalent and financially damaging. The consequences, including data loss, operational shutdowns, and the compounding costs of recovery, are severe for both individuals and organizations. Prevention remains the most cost-effective defense: patching known vulnerabilities promptly, enforcing MFA on all remote access and email accounts, maintaining tested offline backups of critical data, and implementing code signing validation to block malicious executables. Backups are especially critical: an organization with clean, tested, offline backups is typically able to recover without paying a ransom, removing the attacker’s primary leverage. For organizations seeking to reduce their ransomware attack surface through cryptographic controls, code signing integrity, and private key protection, Encryption Consulting provides the tools and expertise to build these defenses before an incident occurs rather than after.

Frequently Asked Questions

What is ransomware and how does it work?

Ransomware is malicious software that gains access to a victim’s systems, encrypts files or locks the system, and demands a ransom payment in exchange for the decryption key. It follows a three-step process: gaining access through phishing, compromised software, or unpatched vulnerabilities; encrypting data using hybrid encryption schemes; and demanding payment in cryptocurrency. Paying does not guarantee decryption or prevent future attacks.

What is the difference between ransomware that encrypts files and ransomware that exfiltrates data?

File-encrypting ransomware renders data inaccessible by encrypting it in place and demands payment for the decryption key. Double-extortion ransomware combines file encryption with data theft and threatens to publish stolen data publicly if the ransom is not paid, giving attackers leverage even against organizations with clean backups. Most active ransomware groups now use double-extortion.

How does code signing help protect against ransomware attacks?

Code signing enables verification that software comes from a trusted publisher and has not been modified since signing. Endpoints enforcing code signing validation reject unsigned or invalidly signed executables, blocking ransomware delivered as malicious software updates or executable payloads. For the supply chain vector specifically, software update mechanisms that enforce signature validation before executing updates will reject ransomware even if it successfully reaches the target system.

Should an organization pay the ransom in a ransomware attack?

Law enforcement agencies generally advise against paying ransoms. Paying does not guarantee a working decryption key, does not prevent additional ransom demands, does not prevent publication of exfiltrated data, and funds future attacks. Organizations with clean, tested, offline backups can typically recover without paying. The decision involves legal, operational, and financial factors and should be made with legal counsel.

What are the most important technical controls for reducing ransomware risk?

The most important controls include: patching known vulnerabilities promptly; enforcing MFA on all remote access, email, and administrative accounts; deploying endpoint detection and response (EDR) tools that recognize ransomware behavioral patterns; maintaining tested offline or air-gapped backups of all critical data; enforcing code signing validation so only signed, trusted executables run in production; implementing network segmentation to prevent lateral spread after initial access; and conducting regular employee training on phishing recognition.