Analyzing Macro Malware In Office Documents
Analyzes malicious VBA macros embedded in Microsoft Office documents (Word, Excel...
Install
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill analyzing-macro-malware-in-office-documents -g -a claude-code -y- Repository
- mukul975/Anthropic-Cybersecurity-Skills35.4k
- Category
- Documents
- Updated
- 2mo ago
- License
- Apache-2.0
- Context cost
- Mediumabout 2,788 tokens
- Runs scripts
- Yes, review before use
What it does
Analyzes malicious VBA macros embedded in Microsoft Office documents (Word, Excel, PowerPoint) to identify download cradles, payload execution, persistence mechanisms, and anti-analysis techniques. Uses olevba, oledump, and VBA deobfuscation to extract the attack chain. Activates for requests involving Office macro analysis, VBA malware investigation, maldoc analysis, or document-based threat examination.
Analyzing Macro Malware in Office Documents
When to Use
- A suspicious Office document (.doc, .docm, .xls, .xlsm, .ppt) has been flagged by email security
- Investigating phishing campaigns that deliver weaponized Office documents
- Extracting VBA macro code to identify the payload download URL and execution method
- Analyzing obfuscated VBA code to understand the full attack chain
- Determining if a document uses DDE, ActiveX, or remote template injection instead of macros
Do not use for analyzing non-macro Office threats (DDE, remote template injection); while this skill covers detection of these, specialized analysis may be needed.
Prerequisites
- Python 3.8+ with oletools installed (
pip install oletools) - oledump.py from Didier Stevens (https://blog.didierstevens.com/programs/oledump-py/)
- Isolated analysis VM without Microsoft Office installed (prevents accidental execution)
- XLMDeobfuscator for Excel 4.0 macro analysis (pip install xlmdeobfuscator)
- LibreOffice for safe document rendering (does not execute VBA macros by default)
Workflow
Step 1: Initial Document Triage
Determine if the document contains macros or other active content:
# Quick triage with olevba
olevba suspect.docm
# Check for OLE streams and macros
oleid suspect.docm
# Output indicators:
# VBA Macros: True/False
# XLM Macros: True/False
# External Relationships: True/False (remote template)
# ObjectPool: True/False (embedded objects)
# Flash: True/False (SWF objects)
# Comprehensive OLE analysis
oledump.py suspect.docm
# List all OLE streams with macro indicators
# Streams marked with 'M' contain VBA macros
# Streams marked with 'm' contain macro attributes
Step 2: Extract and Analyze VBA Code
Pull out the complete VBA macro source:
# Extract VBA with full deobfuscation
olevba --decode --deobf suspect.docm
# Extract just the VBA source code
olevba --code suspect.docm > extracted_vba.txt
