Ransomware File Activity
Detection overview
Ransomware is a type of malware that encrypts files and demands payment for their release. The Ransomware File Activity detection identifies suspicious file modifications that indicate potential ransomware activity. This detection focuses on abnormal patterns in file creation, deletion, and encryption, which often occur at high speeds and across multiple directories. Early detection of ransomware file activity is critical in stopping an attack before significant data loss or business disruption occurs.
Triggers
- An internal host is connected to one or more file servers via the SMB protocol and is rapidly reading files and writing files of roughly the same size and with roughly the same file name
- This pattern is highly correlated with how ransomware interacts with file servers
Possible Root Causes
- The internal host is infected with a variant of ransomware
- A benign application on the host is rapidly reading files from and writing files to a networked file share
- A user is compiling a large set of source files located on a file share, causing a pattern of reading and writing files that exhibits a similar pattern
Business Impact
- Ransomware encrypts files and transmits the encryption key to the attacker
- The attacker then attempts to extract a ransom (typically payable in an untraceable cyber currency) from the organization in return for a promise to release the encryption key which allows the files to be recovered
- Even if your organization is willing to pay the ransom, there is no guarantee that the encryption key will be provided by the attacker
- Absent the encryption key, files will have to be restored from a backup and any changes since the last backup will be lost
Steps to Verify
- Examine the sample files referenced in the detection and see if the original files are missing and the files that have replaced them carry strange but similar file names or file extensions
- Check the directory in which the files reside for ransom notes with instructions on how to pay the ransom and retrieve the encryption key
FAQ
How can we differentiate between ransomware activity and legitimate file operations?
Look for unusual patterns such as rapid file reads/writes, altered file names/extensions, and the presence of ransom notes. Legitimate operations typically don't exhibit these patterns simultaneously.
What are the first steps to take when ransomware file activity is detected?
Immediately isolate the affected system, examine sample files for encryption signs, and check for ransom notes. Notify the cybersecurity team to initiate an incident response.
Should an organization ever consider paying the ransom?
Paying the ransom is risky and not recommended as it does not guarantee file recovery and might encourage further malicious attacks. It's crucial to focus on prevention and robust response strategies instead.
How can backups help in responding to a ransomware attack?
Regular and secure backups can be a lifeline in ransomware situations, allowing organizations to restore encrypted data without succumbing to ransom demands. It's essential that backups are updated frequently and stored securely, ideally disconnected from the main network.
How can ransomware be detected proactively?
Utilize advanced threat detection systems like the Vectra AI Platform, monitor for unusual network traffic, and regularly conduct security audits.
What role does employee training play in preventing ransomware attacks?
Training employees in recognizing phishing emails and other common attack vectors is crucial in preventing initial ransomware infiltration.
Ransomware File Activity
Possible root causes
Malicious Detection
Attackers deploy ransomware to encrypt an organization’s critical files and demand ransom payments for decryption. Modern ransomware strains operate autonomously, scanning directories for targeted file types and encrypting them in bulk. Attackers often use compromised credentials, remote access tools, or exploits to deploy ransomware within a network. Some ransomware variants also attempt to delete backups and shadow copies, making recovery more difficult.
Benign Detection
Certain legitimate processes may resemble ransomware-like activity. Automated backup systems, log rotation services, and large-scale file migrations can generate high-volume file modifications. Additionally, security software conducting mass file scans or integrity checks may also exhibit similar patterns. However, these benign activities usually follow predictable schedules and occur within known applications, making them distinguishable from true ransomware behavior.
Ransomware File Activity
Example scenarios
Ransomware File Activity
Business impact
If this detection indicates a genuine threat, the organization faces significant risks:
Data encryption and loss
Ransomware attacks can render critical business files inaccessible, disrupting operations and causing financial loss.
Operational downtime
Systems infected with ransomware often require isolation, investigation, and restoration, leading to business interruptions.
Reputational and legal consequences
A successful ransomware attack can result in data breaches, regulatory fines, and loss of customer trust.
Ransomware File Activity
Steps to investigate
Identify the affected host
Determine which system is exhibiting the suspicious file activity and whether multiple systems are affected.
Analyze the process responsible for file modifications
Investigate the specific processes modifying files and check if they align with known ransomware behaviors.
Review recent account activity
Examine login patterns, privilege escalation attempts, and lateral movement to identify possible attacker actions.
Check for ransom notes or indicators of compromise
Look for ransom demand files, unusual file extensions, and deleted shadow copies that indicate active ransomware infection.
Ransomware File Activity
Related detections
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