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

Static analysis result for SHA-256 3bc461557b494696…

MALICIOUS

Office (OOXML) / .DOCX

538.2 KB Created: 2026-01-10 16:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2026-03-06
MD5: 01fafc32682a5a5a78e9b320570c093c SHA-1: 410d45ade900e795cd5a9d55451c460aafbeb033 SHA-256: 3bc461557b49469631359401c244ca25f76f3305e26c96f485fe4749aa23f6a2
542 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 an RTF object. This RTF object contains multiple critical vulnerabilities, including CVE-2017-11882 (Equation Editor) and CVE-2017-8759 (MSXML SAX OLE activation), which are used to execute embedded OLE objects. The RTF also contains excessive hex data and a PE header, indicating it's designed to deliver an executable. The presence of CVE-2026-21514 further suggests a sophisticated exploit chain. The primary attack vector is likely spearphishing, with the embedded RTF acting as a loader for a second-stage payload.

Heuristics 13

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/acke.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/acke.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.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    (in altChunk RTF word/acke.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.
  • CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514
    (in altChunk RTF word/acke.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/acke.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.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    (in altChunk RTF word/acke.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/acke.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/acke.rtf) RTF contains ~1695KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/acke.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/acke.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://ocsp.verisign.com0
    • 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
    • https://www.verisign.com/rpa
    • http://csc3-2010-crl.verisign.com/CSC3-2010.crl0D
    • https://www.verisign.com/rpa0
    • http://csc3-2010-aia.verisign.com/CSC3-2010.cer0
    • https://www.verisign.com/cps0*
    • http://logo.verisign.com/vslogo.gif04
    • http://crl.verisign.com/pca3-g5.crl04
    • https://www.globalsign.com/repository/0
    • http://ocsp.globalsign.com/ca/gstsacasha384g40C
    • http://secure.globalsign.com/cacert/gstsacasha384g4.crt0
    • http://crl.globalsign.com/ca/gstsacasha384g4.crl0
    • http://ocsp2.globalsign.com/rootr606
    • http://crl.globalsign.com/root-r6.crl0G
    • 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
48d308a83f8022a6c78658dec9cd9d19ee8861ea66ed6d9e23cde722e561db72
rtf-objdata-decoded RTF \objdata at offset 0xAF79F 743914 bytes
objdata_01_off002262cf.bin
da8cb70cfd8a429b702a62e2fdaacf621665f3e786e20e63a2796a2f2e40550b
rtf-objdata-decoded RTF \objdata at offset 0x2262CF 610306 bytes
rtf_svb_00000009.zip
28fc295dafc0bcccd998d6dc34a4e9ae47eb34cb74cb4b892eb6454833467799
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116932 bytes