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

Static analysis result for SHA-256 4fa15e271c89ced8…

MALICIOUS

Office (OOXML) / .DOCX

271.8 KB Created: 2021-04-18 19:39:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2026-03-30
MD5: c424e479b40238d1b5dc10df5b7eb3c3 SHA-1: 5040e3cba69fe39df6ee0f793c2859641b9210ce SHA-256: 4fa15e271c89ced8724966e1a53edd2f7f4434c6f58abf501599c8b98f005435
382 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Embedded Link T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter T1059.003 Command and Scripting Interpreter: Windows Command Shell

The sample is a DOCX file that leverages an embedded RTF object containing exploits for CVE-2017-11882 (Equation Editor) and CVE-2017-8759 (MSXML SAX OLE activation). The RTF object also contains excessive hex data and an OLE object that forces activation via \objupdate, indicating a likely attempt to execute arbitrary code. The presence of CVE-2026-21514 further suggests a sophisticated exploit chain. The primary attack vector appears to be exploiting these vulnerabilities to download and execute a secondary payload.

Heuristics 10

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/hroug.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/hroug.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/hroug.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/hroug.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/hroug.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/hroug.rtf) RTF contains ~1027KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/hroug.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/hroug.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
3bbda98d32d15b25ff48d32933b5516bc75512f5d35989a94b029db07d425b13
rtf-objdata-decoded RTF \objdata at offset 0xAF79F 84797 bytes
objdata_01_off000e81d6.bin
31d0b0c8736350c29d658081251eef2ad4e59509fe8222d5a28340dc0162ca79
rtf-objdata-decoded RTF \objdata at offset 0xE81D6 583987 bytes
rtf_svb_00000009.zip
28fc295dafc0bcccd998d6dc34a4e9ae47eb34cb74cb4b892eb6454833467799
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116932 bytes