MALICIOUS
342
Risk Score
Malware Insights
MITRE ATT&CK
T1566.001 Spearphishing Attachment
T1203 Exploitation for Client Execution
The sample is a Microsoft Office document that leverages an altChunk to import an RTF object. This RTF object contains embedded OLE objects and exploits known vulnerabilities, specifically CVE-2017-11882 and CVE-2017-8759, related to the Equation Editor and MSXML SAX parsing. The presence of these exploits indicates an attempt to achieve arbitrary code execution, likely for downloading and running a secondary payload. No specific malware family was identified, but the exploitation vector is clear.
Heuristics 9
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CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759(in altChunk RTF word/nsfer.xml) 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.
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Equation Editor activation — CVE-2017-11882 related high CVE_2017_11882_ACTIVATION_RELATED(in altChunk RTF word/nsfer.xml) 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.
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CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514(in altChunk RTF word/nsfer.xml) 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.
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altChunk imports embedded RTF (RTF injection) critical OOXML_ALTCHUNK_RTFDocument 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.
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Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR(in altChunk RTF word/nsfer.xml) 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.
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\objupdate forces OLE activation high RTF_OBJUPDATE(in altChunk RTF word/nsfer.xml) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
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OLE object data medium RTF_OBJDATA(in altChunk RTF word/nsfer.xml) RTF contains 2 \objdata section(s) — embedded OLE objects
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Embedded OLE object medium RTF_OBJEMB(in altChunk RTF word/nsfer.xml) RTF contains \objemb — embedded OLE object
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Embedded URL info EMBEDDED_URLOne 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.
| Filename | Kind | Source | Size |
|---|---|---|---|
objdata_00_off000a967c.bin1a6e9bbe5686590f0005d1119009e35fe1dd7ae2e1b9ea83f4be78142838e7bd |
rtf-objdata-decoded | RTF \objdata at offset 0xA967C | 64057 bytes |
objdata_01_off000d3a6b.bin2904d9481b5213e862744515dbfde55610c54ceaff4590b92445804024f81476 |
rtf-objdata-decoded | RTF \objdata at offset 0xD3A6B | 694188 bytes |
rtf_svb_00000009.zip28fc295dafc0bcccd998d6dc34a4e9ae47eb34cb74cb4b892eb6454833467799 |
rtf-svb-package | RTF \svb hex-decoded ZIP at offset 0x9 | 116932 bytes |
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