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 [8.5] ›Downloadable rule update v8.5.2

PowerShell Script with Encryption/Decryption Capabilities

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PowerShell Script with Encryption/Decryption Capabilities

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Identifies the use of Cmdlets and methods related to encryption/decryption of files in PowerShell scripts, which malware and offensive security tools can abuse to encrypt data or decrypt payloads to bypass security solutions.

Rule type: query

Rule indices:

  • winlogbeat-*
  • logs-windows.*

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:

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

Version: 2

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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event.category:process and host.os.type:windows and
  powershell.file.script_block_text : (
    (
      "Cryptography.AESManaged" or
      "Cryptography.RijndaelManaged" or
      "Cryptography.SHA1Managed" or
      "Cryptography.SHA256Managed" or
      "Cryptography.SHA384Managed" or
      "Cryptography.SHA512Managed" or
      "Cryptography.SymmetricAlgorithm" or
      "PasswordDeriveBytes" or
      "Rfc2898DeriveBytes"
    ) and
    (
      CipherMode and PaddingMode
    ) and
    (
      ".CreateEncryptor" or
      ".CreateDecryptor"
    )
  ) and not user.id : "S-1-5-18"

Framework: MITRE ATT&CKTM

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