Detection rules › Sigma
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1132.001 Data Encoding: Standard Encoding |
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
CommandLine|contains: FromBase64String
CommandLine|contains: H4sI
CommandLine|contains: MemoryStream
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 |
|