Suspicious FromBase64String Usage On Gzip Archive - Process Creation
Detects attempts of decoding a base64 Gzip archive via PowerShell. This technique is often used as a method to load malicious content into memory afterward.
Detection logic
selection
CommandLine|contains|all:
- FromBase64String
- MemoryStream
- H4sICondition
selectionRaw YAML
title: Suspicious FromBase64String Usage On Gzip Archive - Process Creation
id: d75d6b6b-adb9-48f7-824b-ac2e786efe1f
related:
- id: df69cb1d-b891-4cd9-90c7-d617d90100ce
type: similar
status: test
description: Detects attempts of decoding a base64 Gzip archive via PowerShell. This technique is often used as a method to load malicious content into memory afterward.
references:
- https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=43
author: frack113
date: 2022-12-23
tags:
- attack.command-and-control
- attack.t1132.001
logsource:
product: windows
category: process_creation
detection:
selection:
CommandLine|contains|all:
- 'FromBase64String'
- 'MemoryStream'
- 'H4sI'
condition: selection
falsepositives:
- Legitimate administrative script
level: mediumFalse positives
- Legitimate administrative script
References
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