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

Static analysis result for SHA-256 8fd0ef6fcd50b964…

MALICIOUS

Office (OOXML) / .DOCX

267.7 KB Created: 2026-01-10 16:34:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2026-03-09
MD5: 088d36504d2bba261d41e263bdbf1d9a SHA-1: a1568172bfc2a48a2df380396a176d06a1dbd4f0 SHA-256: 8fd0ef6fcd50b9646244289d7ece7cc523d1efe6521551ae59393f6a37be0b64
382 Risk Score

Malware Insights

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

The sample is a DOCX file that leverages an altChunk to import RTF content. This RTF content contains OLE objects and exploits known vulnerabilities, specifically CVE-2017-11882 (Equation Editor) and CVE-2017-8759 (MSXML SAX OLE activation). The presence of RTF_EQUATION_EDITOR, CVE_2017_11882_ACTIVATION_RELATED, and CVE_2017_8759 heuristics strongly indicates exploitation of these vulnerabilities. The RTF_OBJUPDATE and RTF_EXCESSIVE_HEX heuristics further support the malicious nature of the embedded OLE object. The CVE_2026_21514 heuristic suggests an additional exploit related to Word/OLE security bypass. The primary attack vector appears to be exploiting these vulnerabilities to execute arbitrary code, likely to download and run a secondary payload.

Heuristics 10

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/ctiv.rtf) RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    (in altChunk RTF word/ctiv.rtf) RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514
    (in altChunk RTF word/ctiv.rtf) RTF contains a hidden \svb hex package with DrsE2oDoc and downRevStg drawing compatibility parts. This matches an observed CVE-2026-21514 exploitation shape that manipulates Word's internal document structure and trust decisions.
  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    (in altChunk RTF word/ctiv.rtf) RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/ctiv.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/ctiv.rtf) RTF contains ~1000KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/ctiv.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/ctiv.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://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.microsoft.com/office/drawing/2014/chartex
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2012/wordml
    • http://schemas.microsoft.com/office/word/2015/wordml/symex
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape
    • http://schemas.microsoft.com/office/2006/metadata/properties
    • http://www.w3.org/2001/XMLSchema-instance
    • http://schemas.microsoft.com/office/infopath/2007/PartnerControls
    • http://schemas.openxmlformats.org/officeDocument/2006/customXml
    • http://schemas.microsoft.com/office/2006/metadata/contentType
    • http://schemas.microsoft.com/office/2006/metadata/properties/metaAttributes
    • http://www.w3.org/2001/XMLSchema
    • http://schemas.microsoft.com/office/2006/documentManagement/types
    • http://schemas.openxmlformats.org/package/2006/metadata/core-properties
    • http://purl.org/dc/elements/1.1/
    • http://purl.org/dc/terms/
    • http://schemas.microsoft.com/internal/obd
    • http://dublincore.org/schemas/xmls/qdc/2003/04/02/dc.xsd
    • http://dublincore.org/schemas/xmls/qdc/2003/04/02/dcterms.xsd
    • http://schemas.microsoft.com/sharepoint/v3/contenttype/forms
    • http://schemas.openxmlformats.org/officeDocument/2006/cus�

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000af79f.bin
e78c010be0ab976f39b139ac947555d4aa016cbd406bf364843478a77f4e7127
rtf-objdata-decoded RTF \objdata at offset 0xAF79F 104958 bytes
objdata_01_off000ee2f7.bin
9eb5935f1e6ca9158ca7617a03e6149dac269a423ccdcf0057f755df707237d9
rtf-objdata-decoded RTF \objdata at offset 0xEE2F7 584266 bytes
rtf_svb_00000009.zip
28fc295dafc0bcccd998d6dc34a4e9ae47eb34cb74cb4b892eb6454833467799
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116932 bytes