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PowerShell Script with Encryption/Decryption Capabilities
editPowerShell Script with Encryption/Decryption Capabilities
editIdentifies 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: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Rule query
editevent.category:process 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
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Deobfuscate/Decode Files or Information
- ID: T1140
- Reference URL: https://attack.mitre.org/techniques/T1140/
-
Technique:
- Name: Obfuscated Files or Information
- ID: T1027
- Reference URL: https://attack.mitre.org/techniques/T1027/