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

Static analysis result for SHA-256 f3a689c4713b6748…

MALICIOUS

Office (OOXML) / .DOCX

623.5 KB
MD5: 2c6af0076a8e902a1139869d0e66127f SHA-1: 90adb2abde09fe672dea293629cdcb685c85607c SHA-256: f3a689c4713b6748ddc3fdfe37ba6d5073b93bc0d117b4695c59137faf598bc1
180 Risk Score

Malware Insights

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

The OOXML document utilizes an altChunk to embed an RTF file, which in turn contains OLE objects. The presence of \objupdate and excessive hex data within the RTF suggests that these OLE objects are designed to be activated, likely to execute a malicious payload. The embedded RTF file itself is a key indicator of the attack vector.

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/Liechtenstein.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/Liechtenstein.rtf) RTF contains ~2822KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Liechtenstein.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Liechtenstein.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
90618e0dff0115f152a5a9f74746385997bce0d3b7bc7047d41174409791fbfa		 rtf-objdata-decoded RTF \objdata at offset 0x3A12 1423701 bytes
objdata_01_off002c5d0f.bin
cfdb4a077c5f246e92e6322395cebc5a3dcf8a28c92ec8882aadb5231c9a8a69		 rtf-objdata-decoded RTF \objdata at offset 0x2C5D0F 584266 bytes

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