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Elastic Docs ›Elastic Security Solution [8.6] ›Detections and alerts ›Prebuilt rule reference
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Compression DLL Loaded by Unusual Processedit

Identifies the image load of a compression DLL. Adversaries will often compress and encrypt data in preparation for exfiltration.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: low

Risk score: 21

Runs every: 60m

Searches indices from: now-119m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Collection
  • Data Source: Elastic Endgame
  • Rule Type: BBR

Version: 1

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

library where
  dll.name : ("System.IO.Compression.FileSystem.ni.dll", "System.IO.Compression.ni.dll") and

  /* FP Patterns */
  not process.executable :
      ("?:\\Program Files\\*",
       "?:\\Program Files (x86)\\*",
       "?:\\Windows\\Microsoft.NET\\Framework*\\mscorsvw.exe",
       "?:\\Windows\\System32\\sdiagnhost.exe")

Framework: MITRE ATT&CKTM

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