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Elastic Docs ›Elastic Security Solution [8.8] ›Detections and alerts ›Prebuilt rule reference
« Suspicious Explorer Child Process Suspicious File Creation in /etc for Persistence »

Suspicious File Changes Activity Detectededit

This rule identifies a sequence of 100 file extension rename events within a set of common file paths by the same process in a timespan of 1 second. 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.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Impact
  • Data Source: Elastic Defend

Version: 7

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

sequence by process.entity_id, host.id with maxspan=1s
  [file where host.os.type == "linux" and event.type == "change" and event.action == "rename" and file.extension : "?*"
   and process.executable : ("./*", "/tmp/*", "/var/tmp/*", "/dev/shm/*", "/var/run/*", "/boot/*", "/srv/*", "/run/*") and
   file.path : (
   "/home/*/Downloads/*", "/home/*/Documents/*", "/root/*", "/bin/*", "/usr/bin/*",
   "/opt/*", "/etc/*", "/var/log/*", "/var/lib/log/*", "/var/backup/*", "/var/www/*")] with runs=25

Framework: MITRE ATT&CKTM

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