IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
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Elastic Docs ›Elastic Security Solution [8.2] ›Detections and alerts ›Prebuilt rule reference

Suspicious .NET Code Compilation

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Suspicious .NET Code Compilation

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Identifies suspicious .NET code execution. connections.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

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

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Defense Evasion

Version: 6 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.2.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guide

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## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where event.type in ("start", "process_started") and
process.name : ("csc.exe", "vbc.exe") and process.parent.name :
("wscript.exe", "mshta.exe", "cscript.exe", "wmic.exe", "svchost.exe",
"rundll32.exe", "cmstp.exe", "regsvr32.exe")

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 6 (8.2.0 release)
  • Formatting only
Version 5 (7.16.0 release)
  • Formatting only
Version 4 (7.12.0 release)
  • Formatting only
Version 3 (7.11.2 release)
  • Formatting only
Version 2 (7.11.0 release)

  • Updated query, changed from:

    event.category:process and event.type:(start or process_started) and
process.name:(csc.exe or vbc.exe) and process.parent.name:(wscript.exe
or mshta.exe or wscript.exe or wmic.exe or svchost.exe or rundll32.exe
or cmstp.exe or regsvr32.exe)
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