IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
PowerShell Suspicious Payload Encoded and Compressededit
Identifies the use of .Net functionality for decompression and base64 decoding combined in PowerShell scripts, which Malware and security tools heavily use to deobfuscate payloads and load them directly in memory to bypass defenses.
Rule type: query
Rule indices:
- winlogbeat-*
- 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: 1
Added (Elastic Stack release): 8.0.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positivesedit
Legitimate PowerShell Scripts which makes use of compression and encoding
Rule queryedit
event.category:process and powershell.file.script_block_text : ( (System.IO.Compression.DeflateStream or System.IO.Compression.GzipStream or IO.Compression.DeflateStream or IO.Compression.GzipStream) and FromBase64String )
Threat mappingedit
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/
-
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
-
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/