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skills/deobfuscating-powershell-obfuscated-malware/references/standards.md

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+# Standards and Frameworks Reference
+
+## PowerShell Obfuscation Taxonomy
+
+### Layer Classification
+| Layer | Technique | Example |
+|-------|-----------|---------|
+| L1 | Base64 EncodedCommand | `powershell -enc SQBFAFgA...` |
+| L2 | String Concatenation | `$a='Inv'+'oke'+'-Ex'+'pression'` |
+| L3 | Character Code Array | `[char[]](73,69,88)-join''` |
+| L4 | Tick-Mark Insertion | `` I`nv`oke-Exp`ress`ion `` |
+| L5 | Environment Variable | `$env:COMSPEC[4,15,25]-join''` |
+| L6 | SecureString | `ConvertTo-SecureString ... -Key` |
+| L7 | Compression + Base64 | `IO.Compression.DeflateStream` |
+| L8 | XOR Encoding | `$bytes | %{ $_ -bxor 0x42 }` |
+| L9 | Replace Chain | `.Replace('abc','I').Replace(...)` |
+| L10 | Format String | `("{2}{0}{1}" -f 'ke-','Ex','Invo')` |
+
+### MITRE ATT&CK Mappings
+| Technique | ID | Description |
+|-----------|-----|------------|
+| Command and Scripting Interpreter: PowerShell | T1059.001 | Malicious PowerShell execution |
+| Obfuscated Files or Information | T1027 | Encoding/encryption of scripts |
+| Deobfuscate/Decode Files | T1140 | Runtime deobfuscation |
+| Ingress Tool Transfer | T1105 | Downloading payloads via PS |
+| System Binary Proxy Execution | T1218 | Using trusted binaries |
+
+## PowerShell AST Node Types for Analysis
+
+### Key Expression Nodes
+- `CommandExpression`: Direct command invocations
+- `InvokeMemberExpression`: Method calls on objects
+- `BinaryExpression`: String concatenation operators
+- `ArrayExpression`: Character array construction
+- `SubExpression`: Nested expression evaluation
+- `ExpandableStringExpression`: String interpolation
+
+## References
+- [PowerShell Language Specification](https://docs.microsoft.com/en-us/powershell/scripting/lang-spec/chapter-01)
+- [Invoke-Obfuscation Framework](https://github.com/danielbohannon/Invoke-Obfuscation)
+- [AMSI Interface Documentation](https://docs.microsoft.com/en-us/windows/win32/amsi/)

skills/deobfuscating-powershell-obfuscated-malware/references/workflows.md

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+# PowerShell Deobfuscation Workflows
+
+## Workflow 1: Automated Multi-Layer Deobfuscation
+
+```
+[Obfuscated Script] --> [Identify Techniques] --> [Remove Tick Marks]
+                                                        |
+                                                        v
+                                              [Resolve Concatenation]
+                                                        |
+                                                        v
+                                              [Decode Base64 Layers]
+                                                        |
+                                                        v
+                                              [IEX -> Write-Output]
+                                                        |
+                                                        v
+                                              [Extract Final Payload]
+```
+
+## Workflow 2: AST-Based Analysis
+
+```
+[Script Input] --> [Parse AST] --> [Walk Expression Nodes] --> [Evaluate Expressions]
+                                                                       |
+                                                                       v
+                                                             [Reconstruct Commands]
+                                                                       |
+                                                                       v
+                                                             [Extract IOCs]
+```
+
+## Workflow 3: Dynamic Sandbox Deobfuscation
+
+```
+[Obfuscated Script] --> [Execute in Sandbox] --> [Capture ScriptBlock Logs]
+                                                          |
+                                                          v
+                                                 [Event ID 4104 Analysis]
+                                                          |
+                                                          v
+                                                 [Reconstruct Execution Chain]
+```
+
+### Steps:
+1. **Enable Logging**: Enable PowerShell ScriptBlock logging (Event ID 4104)
+2. **Execute**: Run obfuscated script in isolated sandbox
+3. **Collect**: Gather all ScriptBlock log entries
+4. **Reconstruct**: Assemble deobfuscated script from logged blocks
+5. **Extract**: Pull IOCs from the reconstructed clear-text script