sigma-rules/rules/linux/impact_potential_linux_ransomware_file_encryption.toml

[metadata]
creation_date = "2023/03/20"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/03/20"

[rule]
author = ["Elastic"]
description = """
Ransomware is a type of malware that encrypts a victim's files or systems and demands payment 
(usually in cryptocurrency) in exchange for the decryption key. One important indicator of a 
ransomware attack is the mass encryption of the file system, after which a new file extension 
is added to the file. This rule identifies a sequence of 50 file extension rename events 
by the same process in a timespan of 1 second.
"""
from = "now-9m"
index = ["logs-endpoint.events.*"]
language = "eql"
license = "Elastic License v2"
name = "Suspicious File Changes Activity Detected"
risk_score = 73
rule_id = "28738f9f-7427-4d23-bc69-756708b5f624"
severity = "high"
tags = ["Domain: Endpoint", "OS: Linux", "Use Case: Threat Detection", "Tactic: Impact"]
type = "eql"
query = '''
sequence by host.id, process.entity_id, file.extension with maxspan=1s 
[ file where host.os.type == "linux" and event.type == "change" and 
  event.action == "rename" and file.extension != "" ] with runs=50 | tail 1
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1486"
name = "Data Encrypted for Impact"
reference = "https://attack.mitre.org/techniques/T1486/"


[rule.threat.tactic]
id = "TA0040"
name = "Impact"
reference = "https://attack.mitre.org/tactics/TA0040/"