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

Static analysis result for SHA-256 b4d2ef91e99612fd…

MALICIOUS

Office (OOXML) / .DOCX

672.1 KB Created: 2025-10-22 14:54:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: 73cb4ac852b3411edd9b4533a247b68a SHA-1: b5ac6d0217c7328ea5c0fff047de8f5806da4584 SHA-256: b4d2ef91e99612fd251546acd7c002ee466f1ab90d6982a5cdd810afc979dbfc
500 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample utilizes an OOXML altChunk to import an RTF document, which in turn contains an OLE object. This object is activated via \objupdate and exploits CVE-2017-8759 (MSXML SAX OLE activation) to execute arbitrary code. The presence of PE headers within the RTF data and the auto-update mechanism for executables strongly indicate the download and execution of a secondary payload. The external relationship points to a potential template file used for delivery.

Heuristics 12

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/Engag.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.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    (in altChunk RTF word/Engag.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.
  • 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/Engag.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/Engag.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/Engag.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/Engag.rtf) RTF contains ~1779KB of hex-encoded data inside \objdata sections — may hide a payload
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/settings.xml.rels: file:///C:\Users\John\AppData\Roaming\Microsoft\Templates\Student report with photo.dotx
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Engag.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Engag.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

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000af6e7.bin
f9dff8c4ea144b14accf94f2cbf13f3e99ab64ef56d2c957bfcdfbe08830976f
rtf-objdata-decoded RTF \objdata at offset 0xAF6E7 786026 bytes
objdata_01_off0023ab17.bin
24ee741dd41bc27803d80f81b66eba686fe8f5d17bd847727dc5d94834bd3188
rtf-objdata-decoded RTF \objdata at offset 0x23AB17 584826 bytes
rtf_svb_00000009.zip
008e94dd68af4600885d76f18087f8d35d4040e2308364d905db626e7fc4307c
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116840 bytes
rtf_svb_0043fa13.zip
a463062fa4912b21a38e780ed3e90eaa5c5b691e2da561ae5b20c5c201fb80f6
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x43FA13 963 bytes
rtf_svb_00440ebe.zip
1db5fafdb39a4e25cd63c0d17ee124d74679ca9fa60ca30d59caa7391aab0069
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x440EBE 964 bytes
rtf_svb_0047938d.zip
53fff4488b7672eecc77c890505a45d3ecfc7a7654d7482c0a7d5b59e04ea302
rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x47938D 964 bytes