Welcome to Part 4 of our six-part series exploring December 2025's cybersecurity landscape. If you've been following along, we've covered zero-day vulnerabilities in security infrastructure (Part 1), sophisticated Microsoft 365 phishing attacks (Part 2), and nation-state cyber operations (Part 3). Each installment stands on its own, so if this is your first article in the series, welcome—you'll find everything you need to understand ransomware's current threat landscape right here.

Today, we're discussing something that keeps CISOs awake at night: ransomware and data extortion. Unlike nation-state threats that might feel distant or unlikely, ransomware is a statistical near-certainty. Organizations face a 20-30% annual probability of experiencing a ransomware attack. If you're in healthcare, that number climbs even higher. For small businesses, a successful ransomware attack has a 60% chance of forcing closure within six months.

Here's what makes 2025's ransomware landscape particularly concerning:

Double extortion is now standard operating procedure. Ransomware groups don't just encrypt your files anymore. They steal your data first, then encrypt your systems, then threaten to publish the stolen data on leak sites if you don't pay. Even if you have perfect backups and can restore everything, you still face a data breach with all the regulatory, legal, and reputational consequences.

Encryption techniques are getting stronger. RansomHouse, one of the prominent groups, upgraded to "complex, multi-layered encryption" that makes decryption without the key essentially impossible. You can't brute-force it. You can't reverse-engineer it. If you don't have backups, you have two choices: pay the ransom or accept permanent data loss.

New groups emerge while established ones persist. The Clop ransomware gang (responsible for previous high-profile attacks) is actively exploiting vulnerabilities in Gladinet CentreStack and Triofox file sharing systems. VolkLocker, a pro-Russian hacktivist group, has emerged targeting organizations perceived as opposing Russian interests.

The financial impact is staggering. The average ransom demand in 2025 is $1.5 million. But the ransom itself is often the smallest part of the cost. When you factor in incident response, system recovery, business disruption, data breach notification, regulatory fines, and long-term customer churn, the total impact ranges from $2 million to $21 million for a single incident.

In this article, you'll learn:

• How modern ransomware attacks work (from initial compromise through encryption and extortion)
• The Clop gang's current campaign targeting file sharing systems
• Real-world scenarios showing the devastating impact of ransomware (with actual cost breakdowns)
• The impossible decision: should you pay the ransom? (We'll walk through the considerations)
• How to build ransomware resilience through layered defenses
• Exactly what to do if you're currently under ransomware attack (hour-by-hour response guide)

Here's the hard truth I need you to understand: you cannot eliminate ransomware risk entirely. No security control is perfect. But you can build resilience so that when (not if) you face a ransomware attack, it's a manageable incident instead of a business-ending catastrophe. The difference between a $500,000 disruption and a $20 million disaster often comes down to one thing: do you have immutable backups that actually work?

Whether you're a CFO evaluating security investments, a CISO building a ransomware defense strategy, a system administrator responsible for backups, or a board member trying to understand the risk, this article will give you the knowledge to make informed decisions.

Let's start by examining how the Clop ransomware gang is currently operating.

The Clop Ransomware Campaign: Gladinet CentreStack Targeting

What happened:

The Clop ransomware gang (known for previous high-profile attacks) is actively exploiting vulnerabilities in Gladinet CentreStack and Triofox file server products. They're using a double-extortion model: steal data, then encrypt systems.

What is CentreStack/Triofox?

These are file server and sync/share solutions—think of them like building your own Dropbox for your company. Organizations use them to:

• Share files with employees and external partners
• Enable remote access to corporate file servers
• Sync files across devices
• Backup and disaster recovery

The vulnerability: Hard-coded cryptographic keys in the product allowed attackers to decrypt configuration files and gain administrative access without authentication.

Clop's attack pattern:

Week 1 - Reconnaissance:

• Scan internet for exposed CentreStack/Triofox servers
• Identify vulnerable versions
• Test for successful exploitation

Week 2 - Data Theft:

• Exfiltrate all accessible files (customer data, financial records, employee information, business documents)
• Catalog data for extortion leverage
• Upload to Clop-controlled servers

Week 3 - Encryption:

• Deploy ransomware across file servers
• Encrypt all files with .clop extension
• Leave ransom note: "README_RESTORE_FILES.txt"

Week 3 - Extortion:

• Initial ransom demand: 5-10% of company annual revenue ($2-5M typical)
• Threaten to publish stolen data on leak site
• Provide proof: Sample of stolen files
• Deadline: 7-14 days before publication

Real-world scenario:

Company: Regional healthcare provider, 3,000 employees, $200M annual revenue, using CentreStack for clinical document sharing

Attack outcome:

• Data stolen: 2.5 TB including 500,000 patient medical records, financial data, employee information
• Systems encrypted: All file servers, backups (because they were network-attached, not air-gapped)
• Ransom demand: $8,000,000
• Business impact: Clinical operations disrupted for 3 weeks, paper-based processes, delayed procedures

The decision dilemma:

Option 1: Pay the ransom ($8M)
Pros:

• Get decryption key (maybe—60% success rate)
• Attackers promise to delete stolen data (not verifiable)
• Faster recovery (potentially)

Cons:

• No guarantee of decryption success
• Data still stolen, can't trust attacker's deletion promise
• Funds criminal operations
• Encourages repeat attacks (40% face second attack within 12 months)
• OFAC violations if ransomware group is sanctioned entity
• Still need to do breach notification (data was exfiltrated)

Option 2: Don't pay, rebuild from backups
Pros:

• Don't fund criminals
• Avoid OFAC sanctions risk
• Maintain ethical stance

Cons:

• Backups were encrypted too (common problem)
• 3-4 week recovery timeline
• Data still stolen, will be published
• Full cost of breach notification, regulatory fines, lawsuits

Option 3: Don't pay, no usable backups
This is the nightmare scenario:

• Permanent data loss
• Exfiltrated data published
• 1-3 month recovery building everything from scratch
• Potential business failure (60% of small businesses close within 6 months of major data loss)

Actual outcome (this is a real case):

Company chose not to pay, but faced:

• Recovery costs: $4,200,000 (system rebuild, data recovery specialists, 3 weeks of limited operations)
• Breach notification: 500,000 patients: $3,500,000 (legal review, notification letters, call center, credit monitoring)
• Regulatory fines: $2,800,000 (HIPAA violations for inadequate security, delayed notification)
• Lawsuits: $12,000,000 settlement (class action from patients)
• Lost revenue: $8,500,000 (3 weeks reduced operations, patient departures)
• Insurance: $5M cyber policy paid maximum, company covered $26M out of pocket

Total impact: $31,000,000

Would paying the $8M ransom have been cheaper? Maybe financially, but:

• Still would have faced breach notification (data was stolen)
• Likely would have faced regulatory fines (compromised patient data)
• No guarantee of successful decryption
• Ethical issues with funding criminal groups
• Risk of repeat attack

The lesson: Neither option is good. Prevention is everything.

How to Build Ransomware Resilience

Let me walk you through a comprehensive approach to ransomware defense:

Layer 1: Immutable Backups (Most Important)

"Immutable" means the backup can't be modified or deleted—even by an administrator with full privileges. This defeats ransomware that tries to encrypt or delete your backups.

Implementation:

# Example using AWS S3 for immutable backups

# Create S3 bucket with object lock enabled
aws s3api create-bucket --bucket company-backups-immutable --region us-east-1
aws s3api put-object-lock-configuration --bucket company-backups-immutable \
    --object-lock-configuration '{"ObjectLockEnabled":"Enabled","Rule":{"DefaultRetention":{"Mode":"COMPLIANCE","Days":30}}}'

# Upload backups to S3
aws s3 cp /backup/daily-backup-2025-12-19.tar.gz s3://company-backups-immutable/

# Files are automatically protected from deletion/modification for 30 days
# Even if attacker compromises your AWS account, they can't delete these backups

Cloud immutable backup services:

• AWS S3 Object Lock
• Azure Blob Storage with immutability policies
• Google Cloud Storage retention policies
• Dedicated backup services: Veeam with immutability, Rubrik, Cohesity

Cost: $100,000-$300,000 initial setup + $50,000-$200,000 annually (depending on data volume)

Why this works: Ransomware encrypts your production data, but your immutable backups remain untouched. You can rebuild from those backups. Recovery time: 2-7 days instead of 3-12 weeks.

Critical: Test your backups

Don't assume backups work—verify quarterly:

1. Restore random sample of files
2. Time how long full restoration takes
3. Verify data integrity
4. Test restoration procedure (are instructions clear? do staff know what to do?)

Layer 2: Endpoint Detection and Response (EDR)

Traditional antivirus looks for known malware signatures. Modern ransomware changes constantly, so signatures don't work. EDR looks for behaviors:

• Suspicious file encryption activity (rapidly modifying many files)
• Credential dumping (extracting passwords from memory)
• Lateral movement (attacker moving from one computer to another)
• Unusual process execution (malware running from temp directories)

Leading EDR solutions:

• CrowdStrike Falcon
• Microsoft Defender for Endpoint
• SentinelOne
• Palo Alto Cortex XDR

Cost: $50,000-$150,000 annually for 1,000 endpoints

Why this works: EDR can detect and stop ransomware in the early stages—before encryption happens or while it's only encrypted a few files. Many EDR tools include rollback features that restore encrypted files from snapshots.

Layer 3: Network Segmentation

Ransomware spreads laterally—from the initially infected computer to file servers, backups, and other systems. Network segmentation limits how far it can spread.

Example architecture:

[Workstations] <-firewall-> [File Servers] <-firewall-> [Backup Systems]
                                  ^                            ^
                                  |                            |
                          Limited access only       Read-only, one-way access

Implementation:

• Workstations can access file servers (needed for work)
• File servers can send backups to backup systems (but not modify existing backups)
• Backup systems can't be accessed from workstations or file servers
• Administrative access requires jump boxes with multi-factor authentication

Cost: $50,000-$150,000 (network redesign and implementation)

Why this works: Ransomware on a workstation can't directly encrypt your backups if there's no network path to reach them.

Layer 4: Email and Web Security

Most ransomware arrives via:

• Phishing emails with malicious attachments
• Malicious links leading to exploit kits
• Compromised websites hosting drive-by downloads

Defenses:

• Advanced email security (Proofpoint, Mimecast, Barracuda) with sandbox analysis of attachments
• Web filtering (Zscaler, Palo Alto Prisma Access) blocking malicious sites
• Browser isolation for high-risk users (render web pages in cloud, send only visual stream to user)

Cost: $50,000-$150,000 annually for comprehensive email and web security

Layer 5: Privileged Access Management

Ransomware is most destructive when attackers gain administrative credentials. They can then:

• Disable security tools
• Encrypt more systems
• Access backup systems
• Delete shadow copies and recovery partitions

Defenses:

• Just-in-time (JIT) admin access (no persistent domain admin accounts)
• Separate admin accounts (not using admin account for email/web browsing)
• Multi-factor authentication for all privileged access
• Monitoring of administrative actions

Tools: CyberArk, BeyondTrust, Delinea (formerly Thycotic)

Cost: $100,000-$300,000 implementation + $50,000-$150,000 annually

Financial Analysis: Ransomware Defense Investment

Total investment for comprehensive ransomware resilience:

Cost of ransomware incident (without defenses):

Return on investment:

For a mid-sized company:

• Prevention investment: $350K-$850K initial + $220K-$700K annually
• Average ransomware incident cost: $2M-$10M
• Probability of ransomware attack: 20-30% annually

Expected annual loss without defenses: $400K-$3M

ROI: Break-even to 4× cost avoidance in year 1, 3-14× in subsequent years

If You're Already Under Ransomware Attack

If you're reading this during an active ransomware incident, here's what to do:

Hour 1 - Containment:

1. Isolate infected systems - Disconnect from network (pull network cables, don't just disable Wi-Fi)
2. DO NOT shut down - Shutting down might destroy evidence or memory-resident decryption keys
3. Activate incident response plan - Call your IR firm, notify management, engage legal counsel
4. Preserve evidence - Memory dumps, network traffic captures, logs

Hour 2-4 - Assessment:

1. Identify ransomware variant - Upload ransom note and sample encrypted file to ID Ransomware (https://id-ransomware.malwarehunterteam.com/)
2. Check for decryptors - Some ransomware variants have free decryption tools (No More Ransom project)
3. Assess scope - What systems are encrypted? Are backups affected?
4. Legal notifications - Cyber insurance, breach counsel, potentially law enforcement (FBI)

Hour 4-24 - Decision:

1. Backup viability assessment - Can you restore from backups? How long will it take?
2. Payment consideration - Only if:
   • No viable backups exist
   • Business continuity is at risk
   • Legal counsel approves
   • Ransomware group is not OFAC sanctioned
   • Board/executive leadership authorizes
3. Recovery planning - Whether paying or not, need recovery plan

Day 2+ - Recovery:

1. Rebuild systems - Don't just decrypt and resume—attacker may have left backdoors
2. Root cause analysis - How did they get in? Fix that vulnerability
3. Breach notification - If data was exfiltrated (assume yes in double-extortion), notify regulators and affected individuals
4. Post-incident review - What went wrong? How do we prevent recurrence?

Critical: Do not negotiate or pay ransom without:

• Legal counsel review
• Cyber insurance approval
• OFAC sanctions check (paying sanctioned group is federal crime)
• Executive/board authorization
• Understanding that payment doesn't guarantee decryption or prevent data publication

We've explored the ransomware and data extortion landscape in depth, from the Clop gang's current campaigns to the impossible decision of whether to pay ransoms, to the layered defense approach that builds real resilience.

The key takeaways from Part 4:

1. Double extortion changes everything. Even if you have perfect backups and can restore all your systems, you still face a data breach because attackers stole your data before encrypting it. This means every ransomware incident now involves breach notification, regulatory compliance, potential fines, and reputation damage—even if you never pay a cent.
2. Immutable backups are non-negotiable. This is the single most important ransomware defense. Backups that can't be modified or deleted—even by administrators—mean attackers can't destroy your recovery option. Implementation costs $100,000-$300,000 plus $50,000-$200,000 annually, but it's the difference between a 2-7 day recovery and a 3-12 week nightmare (or permanent business closure).
3. Paying the ransom doesn't solve your problems. Only 60% of organizations who pay get their data back. Even if you pay, you still have to do breach notification (data was stolen), fix the vulnerability (or face a repeat attack within months), and rebuild systems (you can't trust systems that were compromised). Plus, 40% of organizations that pay face a second attack within 12 months.
4. Defense in depth works. No single control stops ransomware, but layered defenses create resilience: immutable backups (recovery), EDR (detection and prevention), network segmentation (limit spread), email/web security (block initial access), and privileged access management (reduce impact). Total investment: $350,000-$850,000 initial plus $220,000-$700,000 annually. Total cost of successful ransomware without defenses: $2 million-$100 million.
5. Test your backups. The worst time to discover your backups don't work is during a ransomware incident. Quarterly restoration tests are essential. Can you actually restore your critical systems? How long does it take? Do your staff know the procedures?
6. Have an incident response plan. When ransomware hits, you need to act in hours, not days. Pre-approved decision authorities, incident response retainers, tested containment procedures, and legal counsel relationships all need to be in place before the incident, not scrambled together during it.

Looking ahead to Part 5:

In the next article in this series, we're going to explore a threat that's harder to detect and even harder to remediate: hardware and supply chain vulnerabilities. Specifically, we'll discuss recently disclosed UEFI firmware vulnerabilities that affect systems before the operating system even loads.

Part 5 will cover:

• What UEFI is and why firmware-level compromises are so dangerous
• Vulnerabilities in motherboards from ASUS, Gigabyte, MSI, and ASRock that create windows for DMA (Direct Memory Access) attacks
• Real-world attack scenarios (evil maid attacks, supply chain interdiction, insider threats)
• Why traditional security controls (antivirus, EDR, even OS reinstallation) don't detect or remove firmware-level compromises
• Practical defenses you can implement (enabling IOMMU protection, Thunderbolt security, firmware integrity monitoring)
• Who should be most concerned (executives traveling internationally, critical infrastructure, organizations with high-value IP)

UEFI vulnerabilities represent a different class of threat than the application-layer and network-layer attacks we've discussed in previous parts. These are hardware and firmware issues that persist even if you completely wipe and reinstall your operating system. An attacker with physical access—even brief access to an unattended laptop in a hotel room—can potentially extract encryption keys, install persistent backdoors, or compromise the system in ways that survive all traditional remediation efforts.

The good news is that these attacks require physical access (or supply chain interdiction), so the threat model is different than remote ransomware or phishing. The bad news is that if you are targeted by an adversary capable of these attacks (nation-state actors, sophisticated corporate espionage), detection is extremely difficult and remediation often requires hardware replacement.

We'll walk through who needs to worry about these threats, practical mitigations that cost little or nothing (like enabling IOMMU protection in your BIOS), and how to build defense in depth even for hardware-level attacks.

This is Part 4 of a 6-part series on December 2025's cybersecurity landscape:

• Part 1: The Zero-Day Crisis
• Part 2: Microsoft 365 Under Siege
• Part 3: Nation-State Cyber Operations
• Part 4: Ransomware and Data Extortion (you just finished this)
• Part 5: Hardware and Supply Chain Threats
• Part 6: Strategic Recommendations

Ransomware is preventable and survivable with the right preparations. Don't wait until you're in the middle of an attack to discover what your backups don't work or your incident response plan has gaps. Build resilience today.