How to identify ransomware and what to do about it
Updated on October 20, 2022, by Xcitium
How to Identify Ransomware
Ransomware can often be identified by sudden file encryption, inaccessible data, ransom notes, unusual file extensions, and abnormal system behavior. Organizations may also notice unauthorized encryption activity, spikes in CPU usage, suspicious network traffic, or users losing access to critical files. Early detection is essential to limit damage and prevent ransomware from spreading across the network.
Common Signs of a Ransomware Attack
Look for these indicators:
- Files suddenly become inaccessible.
- File extensions change unexpectedly.
- Ransom notes appear on desktops or folders.
- Unusual file encryption activity occurs.
- Shared drives become unavailable.
- System performance decreases significantly.
- Security tools are disabled.
- Suspicious network activity increases.
- Backups become inaccessible.
- Users report missing or encrypted files.
The more indicators that appear simultaneously, the more likely ransomware is present.
Ransomware Identification Checklist
Use this checklist to determine whether ransomware may be active in your environment.
| Indicator | Potential Ransomware Sign |
|---|---|
| Files encrypted unexpectedly | Yes |
| New file extensions added | Yes |
| Ransom note displayed | Yes |
| Large volumes of file modifications | Yes |
| Security software disabled | Yes |
| Suspicious PowerShell activity | Yes |
| Unusual outbound network connections | Yes |
| Missing backups | Yes |
| Unauthorized privilege escalation | Yes |
| Users locked out of files | Yes |
If multiple indicators are present, immediate incident response actions should be initiated.
It’s easy to identify ransomware by the fact that it displays a message on screen demanding payment. What you need to know is how to deal with the different forms of ransomware. With that in mind, here is a guide on how to identify ransomware and what to do about it.
Understanding the three main forms of ransomware
The three main forms of ransomware are scareware, lockware, and encryption ransomware. Scareware and lockware are both, essentially, intimidation tactics.
Scareware sends a frightening message intended to make people pay up. Lockware actually does make your device freeze. It is, however, very easy to undo this, as long as you keep calm. This means that, as with scareware, the real power of lockware is in the message it sends.
Encryption ransomware, by contrast, really does encrypt some or all of your files and the only way to decrypt them is to use the right decryption key. This means that cyberattackers do not need to send intimidating messages. They just need to tell you how much they want, by when and in what way.
There is, however, a slight twist on this in that scareware can try to pass itself off as encryption ransomware. You should be able to identify this fairly quickly as long as you keep calm.
Dealing with a ransomware infection
Dealing with a ransomware infection itself is usually quite easy. For scareware and encryption ransomware all you generally need to do is install a reputable anti-malware program and have it scan your computer. For lockware, boot into safe mode and see if you can install a reputable anti-malware program and have it scan your computer. If that doesn’t work, restore to a previous time point (before the attack) and then install a reputable anti-malware program and have it scan your computer.
If you’re dealing with scareware or lockware then, in practical terms, that will be the end of the matter. It is, however, advisable to see if you can work out how the infection got into your system in the first place and take steps to deal with it. If, however, you’re dealing with encryption ransomware then you still need to take action to restore the encrypted files from a backup. This should emphasize the importance of having a ransomware-proof data backup.
Storing your data safely
Although your aim should always be to prevent ransomware from entering into your system, it’s very much recommended to think about how you can protect yourself from its worst effects if your defenses fail. There are two key steps to making this happen.
First of all, you need to store all sensitive data encrypted. The practical definition of sensitive data is “data you want to keep private”. As a minimum, you should encrypt any personally-identifiable data. This includes data from your own employees.
It is impossible to overstate the importance of this since encryption ransomware attacks are increasingly being combined with data theft and having personal data stolen could, rather ironically, land you on the wrong side of the law.
Secondly, you need to ensure that you have a ransomware-proof data backup system. This means that you need an off-site data backup as well as a local one. This is because local data backups are just too vulnerable to compromise if the production system is attacked.
Ideally, you want to be able to restore to different time points so you have a bit of breathing space if it takes time to pick up on the attack. You could reduce the cost of holding onto older databases by moving them into slower storage.
The Typical Stages of a Ransomware Attack
Understanding the attack lifecycle can help organizations identify ransomware earlier.
Stage 1: Initial Access
Attackers gain entry through:
- Phishing emails
- Compromised credentials
- Vulnerability exploitation
- Malicious downloads
Stage 2: Persistence
The malware establishes a foothold on the device or network.
Stage 3: Lateral Movement
Attackers attempt to spread across systems and applications.
Stage 4: Data Discovery
Sensitive files and assets are identified.
Stage 5: Encryption
Files are encrypted and made inaccessible.
Stage 6: Ransom Demand
Victims receive instructions for payment and data recovery.
Recognizing activity before encryption begins can significantly reduce business impact.
Early Warning Signs of Ransomware
Before encryption starts, organizations may observe:
- Unusual login activity
- Privilege escalation attempts
- Disabled antivirus software
- Suspicious PowerShell execution
- Large file access events
- Unexpected account creation
- Increased network scanning activity
- Connections to known malicious domains
These behaviors often indicate ransomware preparation activities.
Ransomware vs Common System Problems
| Symptom | Ransomware | Normal System Issue |
|---|---|---|
| File encryption | Yes | No |
| Ransom notes | Yes | No |
| Changed file extensions | Yes | No |
| Inaccessible files | Common | Rare |
| High CPU usage | Possible | Possible |
| Network anomalies | Common | Less common |
| Disabled security tools | Common | Rare |
This comparison helps users distinguish ransomware infections from routine technical issues.
How Security Teams Detect Ransomware
Security teams use multiple technologies to identify ransomware.
Endpoint Detection and Response (EDR)
Detects suspicious endpoint behavior and encryption activity.
Extended Detection and Response (XDR)
Correlates indicators across endpoints, networks, and cloud environments.
Security Information and Event Management (SIEM)
Aggregates security logs and identifies suspicious patterns.
Threat Intelligence
Compares observed indicators against known ransomware campaigns.
Behavioral Analytics
Detects abnormal user and system activities associated with ransomware.
Modern ransomware detection relies heavily on behavior rather than signatures alone.
Common Ransomware Indicators of Compromise
Security teams should investigate:
- Unknown file extensions
- Mass file renaming
- Ransom note creation
- Registry modifications
- Disabled backups
- Suspicious scheduled tasks
- Unauthorized administrative activity
- Connections to command-and-control servers
These indicators often help confirm a ransomware infection.
What to Do After Identifying Ransomware
If ransomware is detected:
- Disconnect infected systems immediately.
- Isolate affected devices from the network.
- Preserve forensic evidence.
- Identify the ransomware variant.
- Notify security teams and stakeholders.
- Assess the scope of the attack.
- Begin containment and remediation.
- Restore from clean backups when possible.
- Investigate root cause.
- Strengthen defenses to prevent recurrence.
Fast action can dramatically reduce recovery costs.
Example: Detecting a Ransomware Attack
A finance employee reports that files suddenly display unfamiliar extensions and cannot be opened.
The security team discovers:
- Multiple endpoints encrypting files.
- Antivirus services disabled.
- Large-scale file modification events.
- A ransom note demanding payment.
These indicators confirm ransomware activity and trigger incident response procedures.
Preventing ransomware attacks
Your first line of defense against ransomware is a robust anti-malware program from a reputable cybersecurity company (i.e. not one of the default security applications bundled with the main operating systems). You want one with an integrated firewall and, these days, a cloud-based option is generally the most sensible approach. That way the vendor takes care of all the updates and the majority of the storage and processing is pushed onto the back-end servers. This reduces the load on local devices.
Your second line of defense against ransomware is to make sure that your operating systems and locally-installed applications are all updated promptly. Ideally, they should be updated literally as soon as a security-related patch is released. In the real world, you might want to wait a day or two to ensure that the updates don’t create any major issues, but then you need to make a decision and the decision should generally be to go ahead with the update.
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Frequently Asked Questions About Identifying Ransomware
How can I identify ransomware?
Ransomware can be identified through encrypted files, ransom notes, changed file extensions, inaccessible data, and unusual system activity.
What are the first signs of ransomware?
Common early signs include unusual file access patterns, disabled security tools, suspicious login activity, and unexpected system behavior.
Can ransomware be detected before encryption?
Yes. Modern EDR, XDR, and behavioral analytics solutions can identify suspicious activity before encryption begins.
What does a ransomware note look like?
A ransomware note typically contains payment instructions, deadlines, and information about recovering encrypted files.
What tools help identify ransomware?
Organizations commonly use:
- EDR solutions
- XDR platforms
- SIEM systems
- Threat intelligence platforms
- Malware analysis tools
How quickly should ransomware be reported?
Immediately. Delayed reporting increases the likelihood of lateral movement and additional damage.
Related Resources:
Protect Your Networks From Ransomware
Ransomware Protection
Ransomware Removal
Ransomware Virus
Admin Monitoring Software
