Silent Ransomware: The Attack You Don’t See Coming

Ransomware campaigns have changed. It’s no longer just about locking files and demanding payment. Increasingly, attackers are getting what they want before they launch the encryption payload.

Let’s explore how these “silent ransomware” attacks work, why traditional defenses often miss the early warning signs, and what practical steps you can take to detect and stop them before they cause harm.

What is silent ransomware?

Silent ransomware is a newer approach to cyber attacks. It focuses on quietly stealing sensitive data (such as customer records, phone numbers, intellectual property, and internal emails) and only then triggering a ransom demand.

Encrypting files still happens, but by that point, it’s just one part of the pressure. Victims now face the added threat of public exposure, regulatory fallout, and reputational damage.

What makes this tactic particularly dangerous is how subtle it is. There’s no flashing ransom note at the start. No sudden system freeze. Just sensitive data quietly moving out of the network, often undetected.

What makes silent ransomware so dangerous?

Traditional ransomware groups are noisy. The moment they hit, files are locked, systems slow to a crawl, and a ransom note demands your attention. It’s disruptive by design.

Silent ransomware takes a different approach. Instead of triggering alarms, it moves quietly through your network, collecting sensitive data long before any encryption takes place. By the time a ransom demand appears, the damage is already done, and attackers now have a copy of your most valuable information.

This makes containment far more difficult. Backups can help restore systems, but they don’t undo a data breach. Attackers can threaten to leak stolen files, sell them on dark web markets, or share them with competitors. And because the initial activity is subtle, it often goes unnoticed until it’s too late.

Ultimately, silent ransomware adds another layer of risk. It’s not just about system downtime anymore. It’s about losing control of your data. And that changes how organizations need to think about detection and response.

Tactics and techniques behind the silence

Attackers don’t need to make noise to do damage. In silent ransomware attacks, their goal is to stay under the radar for as long as possible.

Here are a few examples of how they might operate without triggering immediate alarms:

• Use of legitimate tools: Rather than deploying obvious malware, attackers often rely on built-in utilities like PowerShell, RDP to get remote access, or PsExec. Because these tools are used by admins every day, their activity can blend in easily.
• Data staging: Before exfiltration, files are sometimes copied to internal systems or cloud shares to consolidate and compress them. This step, done slowly and in chunks, helps avoid bandwidth spikes that might catch a monitoring tool’s attention.
• Exfiltration over trusted services: Instead of pushing data to a suspicious IP, attackers may use common platforms like Dropbox, Google Drive, or even Slack. These services often aren’t blocked, and traffic to them might not raise red flags.
• Credential harvesting and privilege escalation: By compromising user accounts (especially those with admin rights), attackers can navigate freely, disable logging, or tamper with defenses without raising suspicion.

These are just examples. No two attacks look exactly the same, and threat actors constantly adapt their methods. But what they have in common is a focus on stealth. They operate quietly, avoid detection, and only reveal themselves when they’re ready to demand payment.

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Here’s an example of how a silent ransomware attack might unfold.

1. Initial access: The cybercriminal accesses the system via methods such as phishing emails, social engineering, stolen credentials, or an unpatched VPN.
2. Recon and lateral movement: The attacker maps out the network and looks for valuable systems or data.
3. Data staging: Sensitive files are quietly copied to a central location or jump server, often compressed to make them easier to move.
4. Data exfiltration: The attacker uploads the staged data to an external location, sometimes using trusted services like Dropbox or Google Drive to avoid detection.
5. Ransom note and encryption: Once the data is safely exfiltrated, files are encrypted, systems are locked, and a ransom demand is delivered, now with the added threat of data exposure.

Figure 2: Timeline showing the progression of a silent ransomware attack.

Detection isn’t easy. Here’s why.

Silent ransomware thrives on being overlooked. Most security teams are set up to catch the end of a ransomware attack, such as the encryption, the ransom note, and the obvious damage. But by then, the real problem may have started days earlier.

The challenge is that the early stages look normal on the surface. Attackers use legitimate credentials, standard admin tools, and common cloud services. Nothing gets flagged because nothing looks unusual (at least not at first).

Antivirus software often doesn’t help here. There’s no obvious malware in play. No suspicious binaries. Just familiar tools doing familiar things, in unfamiliar ways.

And if your monitoring focuses on endpoints alone, you might miss lateral movement across the network entirely. All of this makes detection a behavioral problem, not just a technical one.

You’re not looking for a known signature. You’re looking for subtle changes in how people, systems, and data behave over time.

Let’s get some ideas of what that might look like.

Early indicators of silent ransomware attacks

Spotting a silent ransomware attack early means looking for the kinds of things that don’t usually set off alarms (but should).

These attacks are designed to blend in, so the signs are often subtle. But they’re there if you know where to look.

Here are some of the key indicators of compromise (IOCs) that could suggest an attacker is already inside your network:

• Unusual data access patterns: Large file transfers from rarely accessed folders, or activity from users who don’t normally handle sensitive data.
• Anomalous outbound traffic: Data being sent to unknown external domains or cloud platforms not used by your organization, especially in compressed or encrypted formats.
• Off-hours activity: File access or privilege use in the middle of the night, particularly from service accounts or machines that normally aren’t used.
• Abuse of legitimate tools: Increased use of PowerShell, PsExec, or RDP sessions without a clear business justification.
• Sudden archiving or compression: Attackers often compress data before exfiltration. Look for spikes in the use of tools like WinRAR, 7-Zip, or built-in utilities.
• Account behavior drift: A user account suddenly accessing different systems, escalating privileges, or acting outside its normal scope.

No single sign here confirms a ransomware attack in progress. But patterns matter. Spotting one anomaly might not mean much. But spotting three or four together should trigger a closer look.

The key is correlation—linking network activity with user behavior and system events. That’s what gives security teams the context they need to respond before it’s too late.

Silent hacking in action: An example

Not every breach starts with a ransom note. Some attackers are far more patient (and just as dangerous).

Take Chinese APT groups. These state-backed threat actors are known for operating inside networks for months, even years, without detection. Their goal isn’t disruption. It’s access.

One high-profile example involves the group Salt Typhoon, which allegedly infiltrated at least eight U.S. telecom providers over an extended time period. Even after discovery, the U.S. government admitted it could not confirm that all Chinese actors had been removed from the affected networks.

While this wasn’t a ransomware attack, it demonstrates that threat actors don’t need to act quickly to cause damage. In fact, the longer they stay quiet, the more data they can access, and the harder it becomes to clean them out.

This is the same kind of prolonged, stealthy presence seen in silent ransomware operations.

Mitigation: Don’t wait for the lock screen

If you’re only preparing for encryption, you’re already too late. Your defences need to focus on what happens before the ransom note.

Here are some cybersecurity measures to start with:

• Data Loss Prevention (DLP): Monitor and control the movement of sensitive files. Look for unusual downloads, large transfers, or data being compressed unexpectedly.
• Network Detection and Response (NDR): Silent hackers often move laterally across networks before exfiltrating data. NDR helps detect this by spotting abnormal traffic patterns and unauthorised internal connections.
• User Behaviour Analytics (UBA): Track how users typically behave, then flag when something changes. Is an HR account suddenly accessing engineering files? Is a service account transferring gigabytes of data at 3 a.m.? That’s worth investigating.
• File access monitoring: Track who is touching your critical files, when, and how often. Silent ransomware often starts with large volumes of access across servers that most users rarely touch.
• Multi-factor authentication (MFA): Make this mandatory across all systems. This will add one extra layer of security that could stop hackers in their tracks.
• Regular compromise assessments: Even if everything looks fine on the surface, scheduled compromise checks can uncover dormant threats and vulnerabilities.
• External threat intelligence: Use a tool like CybelAngel to proactively identify cyber threats (and players) before they cross into your network.

Your Guide to the Threat Intelligence Revolution

Mitigation isn’t about one tool or one rule. It’s about layering your defences, watching your data, and knowing what “normal” looks like, so you can act fast when it’s not.

Incident response: What to do if it happens

If you detect signs of a silent ransomware attack (or even suspect one) timing is everything.

Start by isolating affected systems to prevent further data movement or encryption. Review logs for unusual file access, outbound traffic, and changes to user permissions.

It’s also essential to preserve evidence; forensic analysis can reveal how the attacker moved, what data was taken, and whether any persistence mechanisms remain.

Engage your incident response team, alert legal and compliance teams, and prepare for coordinated communication.

Silent ransomware is both a cybercrime and a data breach, so expect to address decryption, functionality recovery, and possibly public disclosure.

FAQs

Who is the Silent Ransom Group?

The “Silent Ransom Group” or “Luna Moth” is a cybercriminal gang believed to be using stealthy tactics to exfiltrate data and extort the organization, without encrypting the files. The FBI has been involved in investigating their activities.

Is silent ransomware the same as double extortion?

Not quite.

• Silent ransomware describes the stealthy tactics used to exfiltrate data before any encryption occurs.
• Double extortion refers to the strategy of demanding payment not just to unlock files, but also to prevent the release of stolen data.

Silent ransomware often enables double extortion, but they’re not always one and the same.

Wrapping up

Silent ransomware attacks don’t start with a bang. They creep into systems, and by the time encryption hits, the real damage is already done.

Detecting these threats early means paying attention to subtle signals and investing in tools that give you real visibility across your environment.

To stay ahead of evolving ransomware tactics, try CybelAngel and get proactive protection that sees what others miss.