IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
Elastic Docs ›Elastic Security Solution [8.8] ›Downloadable rule update v8.8.5
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PowerShell Script with Encryption/Decryption Capabilitiesedit

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:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Data Source: PowerShell Logs

Version: 3

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

event.category:process and host.os.type:windows and
powershell.file.script_block_text : (
    CipherMode and
    PaddingMode and
    (
        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 (.CreateDecryptor or .CreateEncryptor)) and not user.id:S-1-5-18

Framework: MITRE ATT&CKTM

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