Base64 Encoded PowerShell Command Detected

 1title: Base64 Encoded PowerShell Command Detected
 2id: e32d4572-9826-4738-b651-95fa63747e8a
 3status: test
 4description: Detects usage of the "FromBase64String" function in the commandline which is used to decode a base64 encoded string
 5references:
 6    - https://gist.github.com/Neo23x0/6af876ee72b51676c82a2db8d2cd3639
 7author: Florian Roth (Nextron Systems)
 8date: 2020/01/29
 9modified: 2023/01/26
10tags:
11    - attack.t1027
12    - attack.defense_evasion
13    - attack.t1140
14    - attack.t1059.001
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection:
20        CommandLine|contains: '::FromBase64String('
21    condition: selection
22falsepositives:
23    - Administrative script libraries
24level: high

References

• Learning Aid - Top Base64 Encodings Table

  

  Learning Aid - Top Base64 Encodings Table. GitHub Gist: instantly share code, notes, and snippets.

  
  Read More

Related rules

• PowerShell -encodedcommand Switch
• Base64 Encoding in CMD or Powershell
• PowerShell Base64 Encoding
• Potential Winnti Dropper Activity
• NTFS Alternate Data Stream