What Is Ransomware Detection?
Ransomware attacks continue to rise at an alarming rate. In 2024, ransomware attacks reached unprecedented levels, with a total of 5,263 incidents—the highest annual count since monitoring began in 2021. The United States remained the primary target, experiencing approximately 50.2% of these attacks, equating to 2,713 cases.
The industrial sector was notably affected, accounting for 27% (1,424) of all ransomware incidents in 2024. This is a 15% increase compared to 2023, this shows the sector’s vulnerability and the significant disruptions caused to critical infrastructure and services.
Despite the surge in attack frequency, there has been a notable decrease in ransomware payments. Total payments dropped by 35% in 2024, amounting to $814 million, down from $1.25 billion in 2023. This decline is attributed to enhanced cybersecurity measures.
Ransomware detection is the process of identifying ransomware activity on a system before or during the early stages of file encryption by monitoring for suspicious behaviour, unusual file activity, or malicious network communication. It helps organisations stop attacks quickly, preventing data theft, large-scale encryption, and service disruption. Effective ransomware detection typically combines behaviour analysis, network monitoring, and automated security tools to block threats in real time.
Ransomware detection refers to the process of identifying the presence of ransomware on a system, either before it can encrypt files or during the early stages of encryption. It involves monitoring systems for suspicious activities and implementing automated responses to halt the attack before significant damage occurs.
Early detection is particularly important with ransomware because once files are encrypted, the damage may be irreversible without proper backups or decryption keys.
How Ransomware Works
Most ransomware attacks follow a similar pattern:
- Initial Access: Attackers gain entry through various vectors, including phishing emails, vulnerable software, compromised credentials, or malicious websites.
- Deployment: The ransomware establishes persistence on the infected system and may attempt to disable security features.
- Command and Control: Many ransomware variants communicate with external servers to receive encryption keys or additional instructions.
- File Discovery: The ransomware scans the system to locate valuable files and data for encryption.
- Data Theft: In double extortion attacks, data is exfiltrated before encryption begins.
- Encryption: Files are encrypted using strong cryptographic algorithms, making them inaccessible without the proper decryption key.
- Ransom Demand: The victim receives instructions on how to pay the ransom, usually in cryptocurrency, to obtain the decryption key.
- Lateral Movement: Advanced ransomware attempts to spread across the network to maximize the impact.
The Need for Early Detection
Early detection of ransomware is a critical component in the fight against this pervasive threat. The earlier an organization can identify a ransomware attack in progress, the better chance it has of preventing widespread encryption and minimizing damage. Most ransomware variants can encrypt thousands of files in minutes. According to security researchers, the average ransomware can encrypt approximately 100,000 files in just 43 minutes. Newer variants not only encrypt data but also steal sensitive company information before encryption begins. If ransomware is detected before data theft occurs, organizations can avoid both encryption damage and costly data breaches.
Common Signs of a Ransomware Attack
- Unusual File Activity: A sudden spike in file access, modification, or creation, especially changes to file extensions
- Suspicious Processes: Unfamiliar processes running on systems or familiar processes behaving abnormally
- Network Traffic Anomalies: Unexpected increases in outbound network traffic or communications with unknown IP addresses
- Performance Issues: Systems running unusually slowly or showing high CPU/disk usage without clear cause
- Security Tool Disruption: Attempts to disable antivirus software, backup systems, or logging mechanisms
Ransomware Preparation Activities
- Attempts to disable or remove security software, monitoring tools, or backup capabilities
- Deletion or modification of backup files, shadow copies, or recovery partitions
- Suspicious clearing or deletion of system event logs to hide malicious activity
- Creation of unauthorized user accounts, especially those with elevated privileges
- Port scanning or unusual authentication attempts indicating efforts to move between systems
Signs of Active Encryption
- File Extension Changes: Files suddenly having unusual extensions (e.g., .encrypted, .locked, .crypto)
- Inability to Open Files: Previously accessible files becoming unreadable or corrupt
- Ransom Notes: Appearance of text files, images, or desktop backgrounds containing ransom instructions
- Application Failures: Applications unable to function due to encrypted configuration files
- File Size Changes: Similar files suddenly having identical or consistent file sizes
Common Ransomware Delivery Methods
Email-Based Attacks
Phishing emails remain the most common ransomware delivery method. These messages often impersonate trusted entities and contain malicious attachments or links. Modern phishing attacks can be highly sophisticated, using social engineering techniques to appear legitimate. Security teams should implement email filtering solutions that examine attachments and links for malicious content. User education about phishing recognition also plays a vital role in preventing these attacks.
Vulnerable Systems and Services
Unpatched software and exposed services provide easy entry points for ransomware operators. Common vulnerabilities include:
- Remote Desktop Protocol (RDP) exposed to the internet
- Virtual Private Network (VPN) services with known vulnerabilities
- Web applications with security flaws
- Outdated operating systems or applications missing security patches
Malicious Websites and Drive-by Downloads
Users visiting compromised websites may unknowingly download ransomware through “drive-by downloads,” where malicious code executes without user interaction. These attacks often exploit browser or plugin vulnerabilities. Web filtering and browser security tools can help detect and block access to known malicious sites. Keeping browsers and plugins updated also reduces the risk of exploitation.
Supply Chain Compromises
Increasingly, attackers compromise trusted software vendors and use legitimate update mechanisms to distribute ransomware. The SolarWinds and Kaseya incidents demonstrated how devastating these supply chain attacks can be.
Ransomware Detection Techniques
- Signature-Based Detection
Signature-based detection compares files against known malware signatures or hashes. This traditional approach works well for identifying known ransomware variants that have been previously analyzed by security researchers.
How it works:
- Security software maintains a database of known malicious file signatures
- Files on the system are scanned and compared against these signatures
- If a match is found, the file is flagged as malicious and blocked from executing
Strengths:
- Fast and efficient for detecting known threats
- Low rate of false positives when properly implemented
- Can identify and block ransomware before execution
Limitations:
- Cannot detect new, unknown ransomware variants
- Ineffective against modified versions of known ransomware
- Requires constant signature updates to remain effective
- Behavior-Based Detection
Rather than looking for specific file signatures, behavior-based detection monitors system activities for patterns associated with ransomware behavior, regardless of the specific variant.
How it works:
- Security tools monitor process behaviors, file system activities, and system changes
- Suspicious actions (like rapid file encryption or deletion of shadow copies) trigger alerts
- When malicious behavior patterns are detected, the process can be terminated
Strengths:
- Can detect new and unknown ransomware variants
- Effective against file-less ransomware that doesn’t write to disk
- Not dependent on prior knowledge of specific ransomware strains
Limitations:
- May allow some file encryption before detection and response
- Potential for false positives when legitimate applications exhibit similar behaviors
- Requires careful tuning to balance detection rates against false alarms
- Traffic Analysis Detection
Traffic analysis detection monitors network communications for patterns associated with ransomware command and control traffic or data exfiltration.
How it works:
- Network monitoring tools analyze traffic patterns, volumes, and destinations
- Unusual outbound connections, especially to known malicious domains, trigger alerts
- Abnormal data transfer patterns that might indicate encryption or exfiltration are flagged
Strengths:
- Can detect ransomware activity before extensive file encryption begins
- Identifies data exfiltration in double extortion attacks
- Works against ransomware variants that communicate with command servers
Limitations:
- Some ransomware operates entirely locally without network communication
- High network traffic environments may make anomaly detection challenging
- Can produce false positives during legitimate high-volume data transfers
- Deception-Based Detection
Deception technology creates decoy files, systems, or credentials that act as tripwires for ransomware activity. When ransomware interacts with these decoys, an alert is triggered.
How it works:
- Decoy files and folders are strategically placed throughout the environment
- These files appear valuable but are monitored for any access or modification
- When ransomware begins encrypting these decoy files, alerts are immediately triggered
Strengths:
- Provides early warning before widespread encryption occurs
- Very low false positive rate, as legitimate users have no reason to access decoys
- Can help identify attack vectors and techniques through analysis of decoy interactions
Limitations:
- Requires proper deployment and management of decoy assets
- Some sophisticated ransomware might attempt to identify and avoid decoys
- Effectiveness depends on decoy placement and convincingness
- Machine Learning-Based Detection
Machine learning models can analyze vast amounts of data to identify patterns and anomalies associated with ransomware that might not be apparent to human analysts.
How it works:
- ML algorithms are trained on data from known ransomware behaviors and legitimate activities
- The models learn to distinguish between normal operations and ransomware indicators
- When suspicious patterns emerge, alerts are generated for investigation
Strengths:
- Can adapt to new ransomware techniques without explicit programming
- Identifies subtle patterns that might escape traditional detection methods
- Improves over time as more data becomes available
Limitations:
- Requires high-quality training data for effective learning
- May produce false positives during initial deployment before model refinement
- Resource-intensive compared to simpler detection methods
Advanced Ransomware Detection Strategies
Integrated Security Information and Event Management (SIEM)
SIEM systems aggregate and correlate data from multiple security tools, providing a comprehensive view of potential ransomware activity across the environment. These platforms can identify patterns that might not be apparent when looking at individual systems. This correlation capability helps detect multi-stage ransomware attacks that might otherwise evade detection. Modern SIEM solutions often incorporate user and entity behavior analytics (UEBA) to establish baselines of normal activity and flag anomalies that might indicate ransomware.
Endpoint Detection and Response (EDR)
EDR solutions provide comprehensive visibility into endpoint activities, enabling detailed monitoring for ransomware behaviors. These tools continuously record endpoint activities, allowing security teams to detect, investigate, and respond to ransomware attempts. The historical data also supports forensic analysis after an incident. Advanced EDR platforms can automatically respond to detected ransomware by isolating affected endpoints, terminating malicious processes, or rolling back changes
Challenges in Ransomware Detection
Evasion Techniques
Modern ransomware employs sophisticated techniques to avoid detection:
- File-less ransomware operates entirely in memory without writing to disk
- Polymorphic code changes its signature with each infection
- Living-off-the-land techniques use legitimate system tools for malicious purposes
- Encryption that mimics legitimate file compression or backup activities
False Positives
Overly sensitive detection systems may flag legitimate activities as potential ransomware:
- System maintenance tasks that modify multiple files
- Backup processes that access large numbers of files
- Encryption used for legitimate security purposes
- Software updates that change numerous system files
