Malicious Office (OOXML) / .DOCX — malware analysis report

Static analysis result for SHA-256 dc56e30cdf770f5c…

MALICIOUS

Office (OOXML) / .DOCX

670.7 KB
MD5: 6fc76748b27a8c813d82f1e4b28bfae3 SHA-1: 5f602fc2e9dbc171fc382898e1e1eeee10524556 SHA-256: dc56e30cdf770f5c105bbd4fdbd358b79160eca995ed7357793b6ced3c68924e
340 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1137.003 DLL Search Order Hijacking T1059.001 PowerShell

The document leverages OOXML altChunk functionality to import an RTF file. This RTF file contains OLE objects that are activated via \objupdate and include excessive hex data, notably a PE header. The critical heuristic OOXML_ALTCHUNK_RTF_AUTOUPDATE_PE indicates that the altChunk RTF auto-updates an embedded executable object. This suggests the document is designed to drop and execute a payload, likely a second-stage malware. No specific family is identifiable from the provided evidence.

Heuristics 9

  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    (in altChunk RTF word/Rwanda.rtf) RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • altChunk imports embedded RTF (RTF injection) critical OOXML_ALTCHUNK_RTF
    Document inlines an embedded RTF via an aFChunk relationship and a <w:altChunk> body element. This is the canonical RTF-injection wrapper used to smuggle RTF exploits (Equation Editor / URL Moniker / objdata) past DOCX-only scanners. Word opens the wrapper and executes the RTF inline. Recursing into the RTF for the exact exploit primitive.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    (in altChunk RTF word/Rwanda.rtf) Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • altChunk RTF auto-updates embedded executable object critical OOXML_ALTCHUNK_RTF_AUTOUPDATE_PE
    OOXML document imports an embedded RTF through altChunk; the RTF contains OLE object data, forces object update, and carries a hex-encoded PE payload. This is a stronger compound exploit-loader shape than a generic altChunk RTF wrapper, but it is not tied to a single CVE unless the nested RTF object primitive also matches one.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/Rwanda.rtf) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    (in altChunk RTF word/Rwanda.rtf) RTF contains ~2627KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Rwanda.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Rwanda.rtf) RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://opendope.org/xpaths
    • http://opendope.org/conditions
    • http://opendope.org/questions
    • http://opendope.org/components
    • http://opendope.org/SmartArt/DataHierarchy
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/main
    • http://schemas.openxmlformats.org/schemaLibrary/2006/main
    • http://schemas.openxmlformats.org/drawingml/2006/chart
    • http://schemas.openxmlformats.org/drawingml/2006/chartDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/diagram
    • http://schemas.openxmlformats.org/drawingml/2006/picture
    • http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing
    • http://schemas.microsoft.com/office/drawing/2008/diagram
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliography
    • http://schemas.openxmlformats.org/drawingml/2006/compatibility
    • http://schemas.openxmlformats.org/drawingml/2006/lockedCanvas

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003a12.bin
52e65e01b22d2e265bb93abe21cc8c43c8b34b9f2603d44a7c38bc291c079ea1
rtf-objdata-decoded RTF \objdata at offset 0x3A12 1326578 bytes
objdata_01_off00296e28.bin
31e3bdb4635082b6f5401bd7688a1baf90019932fe37de5dee9246f0964b7ef4
rtf-objdata-decoded RTF \objdata at offset 0x296E28 584266 bytes