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

Static analysis result for SHA-256 fc15860764d7c000…

MALICIOUS

Office (OOXML) / .DOCX

627.2 KB
MD5: 06ea8b43624321dc64b74ee5ba159858 SHA-1: 9fcbcd845ca6db6cdbe986748619ab95a387dfd5 SHA-256: fc15860764d7c0006d3e2c512267efdc30345b72e6c82f014f717149fa4e7322
180 Risk Score

Malware Insights

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

The OOXML document contains an altChunk that imports an RTF file, which in turn contains OLE objects. The presence of RTF_OBJDATA, RTF_OBJEMB, and RTF_OBJUPDATE heuristics indicates that these embedded OLE objects are designed to be activated and executed. The RTF_EXCESSIVE_HEX heuristic suggests that the OLE object contains obfuscated or malicious code. The primary attack vector appears to be the exploitation of OLE object handling within Microsoft Office documents to deliver a 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/Lesotho.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/Lesotho.rtf) RTF contains ~2831KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Lesotho.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Lesotho.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
36857bd91044c28d6b0d0ea7388bcdc69a14a018df0461623aebf09663872287		 rtf-objdata-decoded RTF \objdata at offset 0x3A12 1427797 bytes
objdata_01_off002c7d0f.bin
cfdb4a077c5f246e92e6322395cebc5a3dcf8a28c92ec8882aadb5231c9a8a69		 rtf-objdata-decoded RTF \objdata at offset 0x2C7D0F 584266 bytes

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