Detection rules › Sigma
PowerShell Base64 Encoded FromBase64String Cmdlet
Detects usage of a base64 encoded "FromBase64String" cmdlet in a process command line
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1059.001 Command and Scripting Interpreter: PowerShell |
| Defense Evasion | T1140 Deobfuscate/Decode Files or Information |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Security-Auditing | 4688 | A new process has been created. |
Stages and Predicates
Stage 1: selection
or:
CommandLine|contains: '6ADoARgByAG8AbQBCAGEAcwBlADYANABTAHQAcgBpAG4AZw'
CommandLine|contains: '::FromBase64String'
CommandLine|contains: 'OgA6AEYAcgBvAG0AQgBhAHMAZQA2ADQAUwB0AHIAaQBuAGcA'
CommandLine|contains: 'oAOgBGAHIAbwBtAEIAYQBzAGUANgA0AFMAdAByAGkAbgBnA'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|