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

Static analysis result for SHA-256 8c03f11507d40e8e…

MALICIOUS

Office (OOXML) / .DOCX

623.2 KB
MD5: fa253086069ee68d2b64101ea8e24061 SHA-1: 2bc6128ee30c76fd6f6801db49d065f941f5f29a SHA-256: 8c03f11507d40e8eb18db80aecf07b527ebcdfd7dfca157e6dc3bb6a722a6c64
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The OOXML document utilizes an altChunk to import an external RTF file, which in turn contains embedded OLE objects. The presence of RTF_OBJDATA, RTF_OBJEMB, and critically, RTF_OBJUPDATE heuristics indicates that these embedded objects are designed to be activated, likely executing malicious code. The excessive hex data further suggests obfuscated or packed content within the OLE object. The attack pattern is consistent with exploiting document vulnerabilities to deliver a secondary payload.

Heuristics 6

  • 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.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/Niger.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/Niger.rtf) RTF contains ~2821KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Niger.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Niger.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
5b563f8ef59d2f1401ad0391470822167830a08552f394904646723f01473150		 rtf-objdata-decoded RTF \objdata at offset 0x3A12 1422953 bytes
objdata_01_off002c5737.bin
cfdb4a077c5f246e92e6322395cebc5a3dcf8a28c92ec8882aadb5231c9a8a69		 rtf-objdata-decoded RTF \objdata at offset 0x2C5737 584266 bytes

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